4.10: Autonomic Nervous System Basics
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This section will review key anatomy concepts in the autonomic nervous system (ANS) related to the mechanism of action of medications. For more detailed information regarding the concepts reviewed, use the links provided to review detailed autonomic nervous system content in the Open Stax Anatomy and Physiology book: [1]
Review the basic structure and function of the nervous system
Review the anatomy of sensory perception .
Review the anatomy of motor responses .
Review the divisions of the autonomic nervous system .
Review autonomic reflexes and homeostasis .
Review information on a few drugs that affect the autonomic nervous system .
Components and Functions of the Nervous System
The nervous system has two major components: the central nervous system (CNS) and the peripheral nervous system. See Figure 4.1. [2] The central nervous system (CNS) is composed of the brain and the spinal cord. The peripheral nervous system includes nerves outside the brain and spinal cord and consists of sensory neurons and motor neurons. Sensory neurons sense the environment and conduct signals to the brain that become a conscious perception of that stimulus. This conscious perception may lead to a motor response that is conducted from the brain to the peripheral nervous system via motor neurons to cause a movement. Motor neurons consist of the somatic nervous system that stimulates voluntary movement of muscles and the autonomic nervous system [3] that controls involuntary responses. This chapter will focus on the autonomic nervous system.
The two divisions [4] of the autonomic nervous system are the sympathetic division (SNS) and the parasympathetic division (PNS) . The SNS contains alpha and beta receptors, and the PNS contains nicotinic and muscarinic receptors. Each type of receptor has a specific action when stimulated (see Figure 4.2 for an image of the divisions of the nervous system and the receptors in the ANS).
SNS and PNS Functions and Homeostasis
The sympathetic system is associated with the "fight-or-flight" response, and parasympathetic activity is often referred to as “rest and digest.” See Figure 4.3 [5] to compare the effects on PNS and SNS stimulation on target organs. The autonomic nervous system regulates many of the internal organs through a balance of these two divisions and is instrumental in homeostatic mechanisms in the body. [6]
Stimulation of SNS primarily produces increased heart rate, increased blood pressure via the constriction of blood vessels, and bronchial dilation. In comparison, stimulation of the PNS causes slowing of the heart, lowering of blood pressure due to vasodilation, bronchial constriction, and focuses on stimulating intestinal motility, salivation, and relaxation of the bladder.
Homeostasis is the balance between the two systems. At each target organ, dual innervation determines activity. For example, the heart receives connections from both the sympathetic and parasympathetic divisions. SNS stimulation causes the heart rate to increase, whereas PNS stimulation causes the heart rate to decrease.
To respond to a threat – to “fight or flight” – the sympathetic system stimulates many different target organs to achieve this purpose. For example, if a person sees a grizzly bear in the wilderness, the individual has the choice to stand and fight the bear or to run away. For either choice, several things must occur for additional oxygen and glucose to be delivered to skeletal muscle to fight or run. The respiratory, cardiovascular, and musculoskeletal systems are all activated to breathe rapidly, cause bronchodilation in the lungs to inhale more oxygen, stimulate the heart to pump more blood, and increase blood pressure to deliver it to the muscles. [7] The liver creates more glucose for energy for the muscles to use. The pupils dilate to see the threat (or the escape route) more clearly. Sweating prevents the body from overheating from excess muscle contraction. Since the digestive system is not needed during this time of threat, the body shunts oxygen-rich blood to the skeletal muscles. To coordinate all these targeted responses, catecholamines such as epinephrine and norepinephrine are released in the sympathetic system and disperse to the many neuroreceptors on the target organs simultaneously. [8]
Chemical Signaling in the Autonomic Nervous System
Neurons conduct impulses to the synapse of a target organ. The synapse is a connection between the neuron and its target cell. See Figures 4.4 [9] and 4.5 [10] for images of synapse connections.
Preganglionic Neurons
The synapse is composed o f a preganglionic (presynaptic) neuron and a postganglionic (postsynaptic) neuron. Preganglionic neurons release acetylcholine (ACh) onto nicotinic receptors on the postganglionic neuron. Nicotine, found in tobacco products, also binds to and activates nicotinic receptors, mimicking the effects of ACh. This is worth noting, because if medications were developed to impact the nicotinic receptors, then it would impact both the SNS and PNS systems at the preganglionic level. Instead, most medications target the postganglionic neurons , because each type of postganglionic neuron has different neurotransmitters and different target receptors.
Postganglionic Neurons
There are different types of postganglionic neurons in the SNS and PNS branches of the autonomic nervous system. Postganglionic neurons of the PNS branch are classified as cholinergic , meaning that acetylcholine (ACh) is released, whereas postganglionic neurons of the SNS are classifed as adrenergic , meaning that norepinephrine (NE) is released. The terms cholinergic and adrenergic refer not only to the signal that is released, but also to the class of neuroreceptors that each binds. (See Figure 4.6 for an image of the release of ACh and NE and their attachment to the corresponding adrenergic or nicotinic receptors.)
The cholinergic system of the PNS includes two classes of postganglionic neuroreceptors: the nicotinic receptor and the muscarinic receptor. Both receptor types bind to ACh and cause changes in the target cell. The situation is similar to locks and keys. Imagine two locks—one for a classroom and the other for an office—opened by two separate keys. The classroom key will not open the office door, and the office key will not open the classroom door. This is similar to the specificity of nicotine and muscarine for their receptors. However, a master key can open multiple locks, such as a master key for the biology department that opens both the classroom and the office doors. This is similar to ACh that binds to both types of receptors.
The adrenergic system of the SNS has two major types of neuroreceptors: the alpha (α)-adrenergic receptor and beta (β)-adrenergic receptor. There are two types of α-adrenergic receptors, termed α1 and α2, and there are two types of β-adrenergic receptors, termed β1 and β2. An additional aspect of the adrenergic system is that there is a second neurotransmitter in addition to norepinephrine. The second neurotransmitter is called epinephrine. The chemical difference between norepinephrine and epinephrine is the addition of a methyl group (CH3) in epinephrine. The prefix “nor-” actually refers to this chemical difference in which a methyl group is missing. [11]
The term adrenergic should remind you of the word adrenaline, which is associated with the fight-or-flight response described earlier. Adrenaline and epinephrine are two names for the same molecule. The adrenal gland (in Latin, ad- = “on top of”; renal = “kidney”) secretes adrenaline. The ending “-ine” refers to the chemical being derived, or extracted, from the adrenal gland. [12]
Interactive Activity
Query \(\PageIndex{1}\)
ANS Neuroreceptors and Effects
The effects of stimulating each type of neuroreceptor are outlined in this section and sample uses of medications are provided.
Sympathetic Nervous System
SNS receptors include Alpha-1, Alpha-2, Beta-1, and Beta-2 receptors. Epinephrine and norepinephrine stimulate these receptors, causing the overall fight-or-flight response in various target organs. Medications causing similar effects are called adrenergic agonists , or sympathomimetics , because they mimic the effects of the body’s natural SNS stimulation. On the other hand, adrenergic antagonists block the effects of the SNS receptors. Dopamine also stimulates these receptors, but it is dosage-based. Dopamine causes vasodilation of arteries in the kidney, heart, and brain, depending on the dosage. See Table 4.1 for a comparison of stimulation and inhibition of these SNS receptors.
Receptor |
Effects of Stimulation |
Effects of Inhibition |
|---|---|---|
Alpha-1 |
Contract smooth muscle
CNS stimulation Blood vessels: vasoconstriction to nonessential organs GI: relax smooth muscle and decrease motility Liver: glyconeogenesis Bladder: contraction Uterus: contraction Pupils: dilation Medication example: Pseudoephedrine to treat nasal congestion by vasoconstriction |
Relax smooth muscle
Vasodilation Bladder: Increase urine flow Medication example: Tamsulosin to improve urine flow |
Alpha-2 |
Vasodilation
Medication Example: Clonidine to treat hypertension |
Not used clinically |
Beta-1 |
Primarily stimulates heart with increased heart rate and contractility
Also causes kidneys to release renin Medication example: Dobutamine to treat acute heart failure to increase cardiac output |
“Selective Beta blocker” used to decrease heart rate and blood pressure
Medication example: Metoprolol to decrease heart rate and blood pressure |
Beta-2 |
Primarily relax smooth muscle
Blood vessels: vasodilation Lungs: bronchodilation GI: decreased motility Liver: glyconeogenesis Uterus: relaxation Medication example: Albuterol for bronchodilation |
“Nonselective Beta Blockers” block Beta-1 and Beta-2 receptors so also cause bronchoconstriction
Medication example: Propranolol blocks Beta-1 and Beta-2 receptor so lowers blood pressure but inadvertently causes bronchoconstriction |
Interactive Activity
Query \(\PageIndex{2}\)
Adrenergic Agonists
Adrenergic agonists stimulate Alpha-1, Alpha-2, Beta-1, or Beta-2 receptors. Stimulation of each type of receptor has different effects and are further explained below.
Alpha-1 receptor agonists: Stimulation of Alpha-1 receptors causes vasoconstriction in the periphery, which increases blood pressure. Vasoconstriction also occurs in mucus membranes, which decreases swelling and secretions for patients experiencing upper respiratory infections. Examples of Alpha-1 agonist medications are pseudoephedrine or phenylephrine, used to treat nasal congestion.
Alpha-2 receptor agonists: Stimulation of Alpha-2 receptors reduces CNS stimulation and is primarily used as an antihypertensive or a sedative. An example of an Alpha-2 agonist medication is clonidine, which is used to treat hypertension and is also used to treat attention deficit hyperactivity disorder.
Beta-1 receptor agonists : Stimulation of Beta-1 receptors primarily affects the heart by increasing heart rate and contractility. It also causes the kidneys to release renin. Effects on the heart are described as having a positive chronotropic (increases heart rate), positive inotropic (increases force of contraction), and positive dromotropic (increases speed of conduction between SA and AV node) properties. Medications that stimulate Beta-1 receptors are primarily used during cardiac arrest, acute heart failure, or shock. An example of a Beta-1 receptor agonist medication is dobutamine, which is used to increase cardiac output in someone experiencing acute heart failure or shock. See Figure 4.7 [13] illustrating dromotropic properties of stimulating Beta-1 receptors.
Beta-2 receptor agonists : Stimulation of Beta-2 receptors causes relaxation in smooth muscle in the lungs, GI, uterus, and liver. Medications that stimulate Beta-2 receptors are primarily used to promote bronchodilation, which opens the airway, and are often used to treat patients with asthma or chronic obstructive pulmonary disease (COPD). An example of a Beta-2 receptor agonist medication used in asthma is albuterol. See Figure 4.8 [14] for an illustration of the effects of stimulating Beta-2 receptors in the lungs.
Side effects of Beta-2 receptor agonists are related to stimulation of Beta-2 receptors in other locations in the body. For example, albuterol can cause tachycardia by stimulating Beta-2 receptors in the heart. Stimulation of Beta-2 receptors can also inadvertently cause hyperglycemia in patients with diabetes because of activation of Beta-2 receptors in the liver, causing glyconeogenesis .
Adrenergic Antagonists
Adrenergic antagonist medications inhibit the Alpha-1, Alpha-2, Beta-1, and Beta-2 receptors. The effects of inhibition of each receptor are explained further below.
Alpha-1 antagonists: Alpha-1 antagonists are primarily used to relax smooth muscle in the bladder and cause vasodilation.
Examples include:
- Tamsulosin is used to decrease resistance of an enlarged prostate gland and improve urine flow.
- Prazosin is used to cause vasodilation and decrease blood pressure in patients with hypertension.
Alpha-2 antagonists: This classification is used in research, but has limited clinical application.
Beta Antagonists: There are two types of beta antagonists: selective beta blockers , which inhibit Beta-1 receptors and affect the heart only, and nonselective beta blockers, that block both Beta-1 and Beta-2 receptors, thus affecting both the heart and lungs. Beta blockers are also referred to as having negative chronotropic (decreased heart rate), negative inotropic (decreased force of contraction), and negative dromotropic (decreased speed of conduction between SA and AV nodes) properties. It is also important for a nurse to remember that beta blockers can mask the usual hypoglycemic symptoms of tremor, tachycardia, and nervousness in patients with diabetes.
Beta-1 antagonists: Beta-1 antagonists primarily block receptors in the heart, causing decreased heart rate and decreased blood pressure. An example is metoprolol, a selective beta blocker used to treat high blood pressure, chest pain due to poor blood flow to the heart, and several conditions involving an abnormally fast heart rate.
Beta-2 antagonists: Nonselective beta blockers block Beta-1 receptors and Beta-2 receptors in the lungs. An example is propranolol, which is used to lower blood pressure by decreasing the heart rate and cardiac output. However, it can also cause bronchoconstriction by inadvertently blocking Beta-2 receptors, so it must be used cautiously in patients with asthma or COPD.
Interactive Activity
Query \(\PageIndex{3}\)
Parasympathetic Nervous System
Acetylcholine (ACh) stimulates nicotinic and muscarinic receptors. Drugs that stimulate nicotinic and muscarinic receptors are called cholinergics. Medications are primarily designed to stimulate muscarinic receptors. Nicotine stimulates pre- and post-ganglionic nicotinic receptors, causing muscle relaxation and other CNS effects. An example of a medication designed to stimulate nicotinic receptors is the nicotine patch, used to assist with smoking cessation.
Muscarinic agonists are also called parasympathomimetics and primarily cause smooth muscle contraction, resulting in decreased heart rate, bronchoconstriction, increased gastrointestinal/genitourinary tone, and pupillary constriction. There are two types of muscarinic agonists: direct-acting and indirect-acting. Direct-acting agonists bind to the muscarinic receptor. Indirect-acting muscarinic agonists work by preventing the breakdown of ACh, thus increasing the amount of acetylcholine available to bind receptors.
Examples of direct-acting muscarinic agonist medications include:
- Pilocarpine : Used to treat glaucoma by causing the ciliary muscle to contract and allow for the drainage of aqueous humor
- Bethanechol : Used for urinary retention by stimulating the bladder causing urine output
Examples of indirect-acting muscarinic agonist medications include:
- Pyridostigmine : Used to reverse muscle weakness in patients with myasthenia gravis
- Physostigmine : Used to treat organophosphate insecticide poisoning
- Donepezil : Enhances memory in some patients with early Alzheimer’s disease
Muscarinic antagonists are referred to as anticholinergics or “parasympatholytics.” Anticholinergics inhibit ACh and allow the SNS to dominate, creating similar effects as adrenergics. Their overall use is to relax smooth muscle. “SLUDGE” is a mnemonic commonly used to recall the effects of anticholinergics: S alivation decreased, L acrimation decreased, U rinary retention, D rowsiness/dizziness, G I upset, E yes (blurred vision/dry eyes). Anticholinergics may also cause confusion and constipation and must be used cautiously in the elderly. See Figure 4.9 [15] for an illustration of the "SLUDGE" effects of anticholinergics.
Examples of anticholinergic medications include:
- Atropine : Specific anticholinergic responses are dose-related. Small doses of atropine inhibit salivary and bronchial secretions and sweating; moderate doses dilate the pupil, inhibit accommodation, and increase the heart rate (vagolytic effect); larger doses will decrease motility of the gastrointestinal (GI) and urinary tracts; very large doses will inhibit gastric acid secretion
- Oxybutynin : Relaxes overactive bladder
- Benztropine : Reduces tremor and muscle rigidity in Parkinson’s disease or in treatment of extrapyramidal reactions from antipsychotic medications
- Scopolamine : Decreases GI motility and GI secretions; used for motion sickness and post-operative nausea and vomiting [16] , [17] , [18] , [19]
- Content can be found at https://openstax.org/books/anatomy-and-physiology/pages/12-1-basic-structure-and-function-of-the-nervous-system ↵
- "1201 Overview of Nervous System.jpg" by CNX OpenStax . is licensed under CC BY 4.0 Access for free at https://openstax.org/books/anatomy-and-physiology/pages/12-1-basic-structure-and-function-of-the-nervous-system ↵
- "Component of the Nervous System" by Blaire Babbit at Chippewa Valley Technical College is licensed under CC BY 4.0 ↵
- "Component of the Nervous System" by Blaire Babbit at Chippewa Valley Technical College is licensed under CC BY 4.0 ↵
- "a7 autonomic nervous system" by unknown is licensed under CC BY-NC-SA 3.0 Access for free at https://blog.coturnix.org/2010/08/24/bio101-physiology-regulation-and-control/ ↵
- This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0 . Access for free at Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction ↵
- This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0 . Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction ↵
- This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0 . Access for free at Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction ↵
- "Autonomic Nervous System" by CNX OpenStax is licensed under CC BY 4.0 ↵
- "The Synapse" by CNX OpenStax is licensed under CC BY 4.0 Access for free at https://openstax.org/books/anatomy-and-physiology/pages/12-5-communication-between-neurons ↵
- "Sympathetic and Parasympathetic Pre-and Postganglionic fibers and neuroreceptors" by Dominic Slausen at Chippewa Valley Technical College is licensed under CC BY 4.0 ↵
- This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0 . Access for free at Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction ↵
- " 2018 Conduction System of Heart.jpg " by OpenStax College is licensed under CC BY 3.0 ↵
- "Bronchodilators" by BruceBlaus is licensed under CC BY 4.0 ↵
- ""SLUDGE" effects of Anticholinergics" by Dominic Slausen at Chippewa Valley Technical College is licensed under CC BY 4.0 ↵
- McCuistion, L., Vuljoin-DiMaggio, K., Winton, M, & Yeager, J. (2018). Pharmacology: A patient-centered nursing process approach . Elsevier. ↵
- Gersch, C., Heimgartner, N., Rebar, C., & Willis, L. (Eds.). (2017). P harmacology made incredibly easy . Wolters Kluwer. ↵
- Lilley, L., Collins, S., & Snyder, J. (2014). Pharmacology and the Nursing Process . Elsevier. ↵
- This work is a derivative of Principles of Pharmacology by LibreTexts licensed under CC BY-NC-SA 4.0 ↵


Learning Outcomes
-
Explain the philosophy and practice of palliative care
-
Describe hospice care
-
Summarize Dame Cicely Saunders’ writings about total pain of the dying
-
Differentiate attitudes toward hospice care based on race and ethnicity
Palliative Care
Palliative care
is an interdisciplinary approach to specialized medical and nursing care for people with life-limiting illnesses. It focuses on providing relief from the symptoms, pain, physical stress, and mental stress at any stage of illness, with a goal of improving the quality of life for both the person and their family. Doctors who specialize in palliative care have had training tailored to helping patients and their family members cope with the reality of the impending death and make plans for what will happen after.
Palliative care is provided by a team of physicians, nurses, physiotherapists, occupational therapists, speech-language pathologists, and other health professionals who work together with the primary care physician and referred specialists or other hospital or hospice staff to provide additional support to the patient. It is appropriate at any age and at any stage in a serious illness and can be provided as the main goal of care or along with curative treatment. Although it is an important part of end-of-life care, it is not limited to that stage. Palliative care can be provided across multiple settings including in hospitals, at home, as part of community palliative care programs, and in skilled nursing facilities. Interdisciplinary palliative care teams work with people and their families to clarify goals of care and provide symptom management, psychosocial, and spiritual support.
Hospice
In many other countries, no distinction is made between palliative care and hospice, but in the United States, the terms have different meanings and usages. They both share similar goals of providing symptom relief and pain management, but
hospice care
is a type of care involving palliation without curative intent. Usually, it is used for people with no further options for curing their disease or
in
people who have decided not to pursue further options that are arduous, likely to cause more symptoms, and not likely to succeed.The biggest difference between hospice and palliative care is the type of illness people have, where they are in their illness especially related to prognosis, and their goals/wishes regarding curative treatment. Hospice care under the Medicare Hospice Benefit requires that two physicians certify that a person has less than six months to live if the disease follows its usual course. This does not mean, though, that if a person is still living after six months in hospice he or she will be discharged from the service.
Watch It
Watch this video to better understand the setting, circumstances, and services associated with hospice care.
A link to an interactive elements can be found at the bottom of this page.
You can
view the transcript for “Understanding Hospice Care” here (opens in new window)
.
Hospice care involves caring for dying patients by helping them be as free from pain as possible, providing them with assistance to complete wills and other arrangements for their survivors, giving them social support through the psychological stages of loss, and helping family members cope with the dying process, grief, and bereavement. It focuses on five topics: communication, collaboration, compassionate caring, comfort, and cultural (spiritual) care. Most hospice care does not include medical treatment of disease or resuscitation although some programs administer curative care as well. The patient is allowed to go through the dying process without invasive treatments. Family members who have agreed to put their loved one on hospice may become anxious when the patient begins to experience death. They may believe that feeding or breathing tubes will sustain life and want to change their decision. Hospice workers try to inform the family of what to expect and reassure them that much of what they see is a normal part of the dying process.
Watch It
One aspect of palliative and hospice care is helping dying individuals and their families understand what is happening, and what it may imply for their lives. The following video provides an example of palliative care in a hospital setting.
A YouTube element has been excluded from this version of the text. You can view it online here:
http://pb.libretexts.org/lsdm/?p=432
You can
view the transcript for “How Doctors Tell Patients They’re Dying | Being Mortal | FRONTLINE” here (opens in new window)
.
The History of Hospice
Dame Cicely Saunders was a British registered nurse whose chronic health problems had forced her to pursue a career in medical social work. The relationship she developed with a dying Polish refugee helped solidify her ideas that terminally ill patients needed compassionate care to help address their fears and concerns as well as palliative comfort for physical symptoms. After the refugee’s death, Saunders began volunteering at St Luke’s Home for the Dying Poor, where a physician told her that she could best influence the treatment of the terminally ill as a physician. Saunders entered medical school while continuing her volunteer work at St. Joseph’s. When she achieved her degree in 1957, she took a position there.
Saunders emphasized focusing on the patient rather than the disease and introduced the notion of ‘total pain’, which included psychological, spiritual, emotional, intellectual, and interpersonal aspects of pain, the physical aspects, and even financial and bureaucratic aspects. This focus on the broad effects of death on dying individuals and their families has provided the foundation for modern day practices related to hospice care services.
Saunders experimented with a wide range of opioids for controlling physical pain but also considered the needs of the patient’s family.
Saunders disseminated her philosophy internationally in a series of tours of the United States that began in 1963. In 1967, Saunders opened St. Christopher’s Hospice. Florence Wald, the Dean of Yale School of Nursing who had heard Saunders speak in America, spent a month working with Saunders there in 1969 before bringing the principles of modern hospice care back to the United States, establishing Hospice, Inc. in 1971. Another early hospice program in the United States, Alive Hospice, was founded in Nashville, Tennessee on November 14, 1975. By 1977 the National Hospice Organization had been formed.
Hospice Care in Practice
The early established hospices were independently operated and dedicated to giving patients as much control over their own death process as possible. Today, it is estimated that over 40 million individuals require palliative care, with over 78% of them being of low-income status or living in low-income countries.
It is also estimated, however, that less than 14% of these individuals receive it. This gap is created by restrictive regulatory laws regarding controlled substance medications for pain management, as well as a general lack of adequate training in regards to palliative care within the health professional community. Although hospice care has become more widespread, these new programs are subjected to more rigorous insurance guidelines that dictate the types and amounts of medications used, length of stay, and types of patients who are eligible to receive hospice care. Thus, more patients are being served, but providers have less control over the services they provide, and lengths of stay are more limited. Patients receive palliative care in hospitals and in their homes.
The majority of patients on hospice are cancer patients and they typically do not enter hospice until the last few weeks prior to death. The average length of stay is less than 30 days and many patients are on hospice for less than a week. Oftentimes medications are rubbed into the skin or given in drop form under the tongue to relieve the discomfort of swallowing pills or receiving injections. A hospice care team includes a chaplain as well as nurses and grief counselors to assist spiritual needs in addition to physical ones. When hospice is administered at home, family members may also be part, and sometimes the biggest part, of the care team. Certainly, being in familiar surroundings is preferable to dying in an unfamiliar place. But about 60 to 70 percent of people die in hospitals and another 16 percent die in institutions such as nursing homes. Most hospice programs serve people over 65; few programs are available for terminally ill children.
Hospice care focuses on alleviating physical pain and providing spiritual guidance. Those suffering from Alzheimer’s also experience intellectual pain and frustration as they lose their ability to remember and recognize others. Depression, anger, and frustration are elements of emotional pain, and family members can have tensions that a social worker or clergy member may be able to help resolve. Many patients are concerned with the financial burden their care will create for family members. And bureaucratic pain is also suffered while trying to submit bills and get information about health care benefits or to complete requirements for other legal matters. All of these concerns can be addressed by hospice care teams.
The Hospice Foundation of America notes that not all racial and ethnic groups feel the same way about hospice care.
Certain groups may believe that medical treatment should be pursued on behalf of an ill relative as long as possible and that only God can decide when a person dies. Others may feel very uncomfortable discussing issues of death or being near the deceased family member’s body. The view that hospice care should always be used is not held by everyone and health care providers need to be sensitive to the wishes and beliefs of those they serve. Similarly, the population of individuals using hospice services is not divided evenly by race. Approximately 81% of hospice patients are White, while 8.7% are African American, 8.7% are multiracial, 1.9% are Pacific Islander, and only 0.2% are Native American.
Watch It
The following video from the National Hospice and Palliative Care Organization discusses some of its goals regarding the increase in hospice care availability.
A link to an interactive elements can be found at the bottom of this page.
You can
view the transcript for “NHF Gala 2015 Final Video” here (opens in new window)
.
Glossary
-
hospice
-
a type of care involving palliation without curative intent. Usually, it is used for people with no further options for curing their disease or people who have decided not to pursue further options that are arduous, likely to cause more symptoms, and not likely to succeed.
-
palliative care
-
an interdisciplinary approach to specialized medical and nursing care for people with life-limiting illnesses. It focuses on providing relief from the symptoms, pain, physical stress, and mental stress at any stage of illness, with a goal of improving the quality of life for both the person and their family.
Contributors and Attributions
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Modification, adaptation, and original content.
Authored by
: Sarah Carter, Ph.D., for Lumen Learning.
Provided by
: Lumen Learning.
License
:
CC BY: Attribution
CC licensed content, Shared previously
All rights reserved content


12.4: Treatments and Nutrition
By the end of this section, you should be able to:
- 12.3.1 Identify drug-food interactions for their impact on treatments utilized for cardiovascular disorders.
- 12.3.2 Identify treatments and medications that can cause nutritional deficiencies in clients with cardiovascular disorders.
Drug-Food Interactions with Treatments for Cardiovascular Disorders
Nurses should be aware of the drug and food interactions that can occur with cardiac medications. This section will discuss some of the most common.
Warfarin and Vitamin K
Warfarin keeps blood from coagulating too quickly and is used for treatment of venous thromboembolism and for stroke prevention for certain conditions like atrial fibrillation or mechanical heart valves. Vitamin K works to assist in coagulation. Warfarin and vitamin K work in opposite ways, so the client must be aware that their normal, daily consumption of vitamin K should be consistent. Women typically need about 90 mcg of vitamin K daily; men typically need about 120 mcg. Green, leafy vegetables, Brussels sprouts, broccoli, asparagus, and green tea are all high in vitamin K (Mayo Clinic, 2022b). The clients can eat leafy greens, but they need to eat them in a consistent amount. When a client’s consumption of leafy greens fluctuates, it can cause fluctuations in the effects of warfarin.
Diuretics and Electrolytes
There are a variety of diuretics used for heart failure and a few for hypertension; the most common are the loop diuretics such as furosemide . Diuretic medications decrease the workload of the heart muscle and rid the body of excess fluid, which can cause fluctuations in electrolyte levels , particularly potassium. The nurse should assess the client for (and instruct the client to note signs of) hypokalemia—potassium levels less than 3.5 mEq/L. Symptoms of hypokalemia include constipation, muscle cramps, heart palpitations, and fatigue (Mayo Clinic, 2023a).
Although the loop diuretics are the most common diuretics that are associated with electrolyte imbalances, the clients who are taking other types of diuretics such as potassium-sparing diuretics need to be aware of the risk for hyperkalemia that can develop from the use of these medications (Knott, 2020). Hyperkalemia , or elevated potassium levels, can cause muscle fatigue, paralysis, arrhythmias, and nausea.
Since diuretics help the body to get rid of excess water, there is a risk that sodium—also an electrolyte—can be reduced too much and cause hyponatremia . The nurse should inform clients of signs and symptoms of hyponatremia: nausea and vomiting, weakness, and changes in level of consciousness; extremely low levels of sodium can cause seizures (Sterns, 2022).
Treatments and Medications That Can Cause Nutritional Deficiencies
Clients with cardiovascular disease frequently take one or more prescribed medications that can potentially cause nutritional deficiencies. Diuretics, for example, are used by clients with hypertension, heart-failure, and other cardiac-related conditions. Deficiencies of water-soluble vitamins are related to the use of diuretic therapy which causes increased excretion of these nutrients (Lennie et al., 2018). Other cardiovascular medications associated with nutrient deficiencies include statin medications used to treat hyperlipidemia. Studies have shown that levels of serum CoQ10, important for converting food into energy, decrease with the use of atorvastatin and similar medications (Chong et al., 2021).
Traditionally, sodium has been the focus of research examining the role of nutrition in the management of heart failure (Lennie et al., 2018). However, recent research has expanded the search for nutritional factors that influence the management of clients with heart failure and other cardiovascular diseases. Researchers have found that clients with heart failure frequently experience calcium, folate, magnesium, zinc, and vitamins C, D, E, and K deficiencies (Lennie et al., 2018). These deficiencies can be related not only to medication use, but also other factors. Another related factor to nutritional deficiencies among clients with heart failure is the lack of diet variety (Lennie et al., 2018). These clients frequently experience loss of appetite, feel full after eating only a small amount, and have limited energy to prepare and eat food. They are more likely to eat the same foods repeatedly, limiting their potential to consume a variety of needed nutrients (Lennie et al., 2018).
Read the following clinical scenario and then answer the questions that follow. This case study is a follow-up from Case Study Parts A, B, C, and D.
Recently, Tara has noticed her legs are swelling and she has experienced some shortness of breath with activity, so she schedules an appointment with her primary care provider.
At Tara’s appointment, her provider takes her vital signs and finds her blood pressure is 165/85 mm Hg and her heart rate is 72 beats per minute. She is experiencing crackles in the base of her lungs and 2+ pitting edema to bilateral lower extremities.
The provider is concerned that Tara has developed heart failure and wants the nurse to educate Tara on healthy food choices. The provider places Tara on the diuretic furosemide to decrease Tara’s swelling and a potassium supplement. The provider orders laboratory work that includes a comprehensive metabolic panel and B-type natriuretic peptide.
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“You need to increase the amount of sodium in your diet.”
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“You need to identify a small list of foods that you can easily prepare and eat several times a week.”
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“You may need a vitamin supplement if you are unable to eat a variety of foods.”
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Fried chicken, green beans, and tea
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Grilled fish, steamed vegetables, and water
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Hamburger, chips, and water
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Baked chicken, rice, and white roll


5.23: Reading- Common Ethical Issues in Marketing
Let’s start by taking at look at a hypothetical business situation:
You’re a member of the marketing team for a B2B company that sells software to restaurants. Your product is a point-of-sale system that manages orders, menus, and staff scheduling. While it generally works well, there are sometimes glitches that cause it to drop orders, and the system goes down more often than you would like. You are marketing the system to a major restaurant chain, and they’ve asked for a list of references from current customers. The marketing and sales teams sit around a table reviewing the current customer list trying to decide which references to provide. First, the team screens out those who have complained most vocally about the glitches with the product. There is one customer who told his account manager, “These thing happen with all systems,” so the team thinks he would be a good reference. There’s also a new customer who started using the system recently and hasn’t yet experienced the system down time that other customers have. The team selects that restaurant, as well, and prepares to send the two names to the sales prospect.
Question
Is that ethical? Is it fair and honest to cherry-pick the customer references, selecting only the ones that are unlikely to share negative experiences about your product? To be sure, there’s a range of customer feedback, and not all of it is positive.
Answer
In general, when prospective customers request customer references, they expect to receive favorable ones, and doing so is not a violation of their trust. It’s a lot like a prospective employer’s request for a job candidate’s work references. When you’re marketing yourself for a new job, you name the references who are most likely to report your talents and strengths—you don’t include a crabby boss who never had good things to say about anyone.
The question becomes more challenging when the customer relationship is more complicated. In every case—even the simplest—it’s a judgment call. Suppose your company compensates customers for providing references. A company might give some small thank-you gift to acknowledge that taking reference calls requires time, and that the company appreciates the client’s support. Is that unethical? Possibly. On one hand, it’s reasonable and desirable to express your appreciation to the customer, since part of maintaining the customer relationship is letting customers know that you value them and their time. On the other hand, there’s a risk, especially if the gift is large, that the customer might be influenced or even induced to give your company or product a favorable review. There is a point where the compensation begins to distort the customer dialogue and relationship, and then it’s clearly unethical—and if you’re inducing a customer to alter their behavior in exchange for a gift, it’s bribery.
Marketing professionals face regularly face questions of this kind. Where the organization appreciates a close partnership with a client, a thank-you gift may well be appropriate. The challenge is to choose one of the right size that expresses appreciation but doesn’t compromise the integrity of the client or the marketing organization.
Below is a list that shows how marketing professionals responded to a survey on the most difficult ethical issues they face. [1]
Most Difficult Ethical Issues Marketing Professionals Face
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15% of marketing professionals say bribery is the most difficult ethical issue
- Gifts from outside vendors, payment of questionable commissions, “money under the table”
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14% of marketing professionals say fairness is the most difficult ethical issue
- Unfairly placing company interests over family obligations, taking credit for the work of others, inducing customers to use services not needed, manipulation of others
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12% of marketing professionals say honesty is the most difficult ethical issue
- Lying to customers to obtain orders, misrepresenting services and capabilities
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12% of marketing professionals say price is the most difficult ethical issue
- Differential pricing, charging higher prices than firms with similar products while claiming superiority
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11% of marketing professionals say product is the most difficult ethical issue
- Product safety, product and brand infringement, exaggerated performance claims, products that do not benefit consumers
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10% of marketing professionals say personnel is the most difficult ethical issue
- Firing, hiring, employee evaluation
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5% of marketing professionals say confidentiality is the most difficult ethical issue
- Temptations to use or obtain classified, secret, or competitive information
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4% of marketing professionals say advertising is the most difficult ethical issue
- Crossing the line between exaggeration and misrepresentation, misleading customers
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4% of marketing professionals say manipulation of data is the most difficult ethical issue
- Falsifying figures or misusing statistics or information, distortion
Notice that many of the responses include watchwords like “questionable,” “exaggerated,” “distortion,” and “crossing the line.” In marketing, the greatest challenge is to influence the behavior of the target customer (by getting them to buy) without violating the customer’s trust or acting unethically. With the rise of social media, customers are in a much better position to share frank evaluations of products and services publicly, and this gives marketers a new means of capturing unbiased customer feedback. (It also opens the door to the problem of “fake customer reviews,” but that’s another issue.)
- Lawrence B. Chonko and Shelby D. Hunt, “Ethics and Marketing Management: An Empirical Examination,” Journal of Business Research , Vol. 13, 1985, pp. 339–359. ↵
Contributors and Attributions
- Common Ethical Issues in Marketing. Provided by : Lumen Learning. License : CC BY: Attribution
- Table from Chapter 5: External Considerations in Marketing, in Core Concepts of Marketing. Authored by : John Burnett. Located at : http://www.saylor.org/site/wp-content/uploads/2012/11/Core-Concepts-of-Marketing.pdf . License : CC BY: Attribution
- Tablet POS. Authored by : Travelarz. Provided by : Wikimedia. Located at : https://commons.wikimedia.org/wiki/File:Tablet_POS_HORECA13.jpg . License : CC BY-SA: Attribution-ShareAlike


8.8: Oxidation of Alkenes - Epoxidation and Hydroxylation
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Objectives
After completing this section, you should be able to
- write the equation for the epoxidation of an alkene using meta-chloroperoxybenzoic acid.
- identify the alkene, reagents, or both, that must be used to prepare a given epoxide.
- write the equation for the hydroxylation of an alkene using osmium tetroxide, and draw the structure of the cyclic intermediate.
- draw the structure of the diol formed from the reaction of a given alkene with osmium tetroxide.
- identify the alkene, the reagents, or both, that must be used to prepare a given 1,2-diol.
Key Terms
Make certain that you can define, and use in context, the key terms below.
- diol
- glycol
- hydroxylation
The previous section discussed the reduction of a double bond, so adding hydrogen to the the double bond. This section will discuss oxidation. In organic chemistry, this is a reaction that where the carbon atom loses electron density, which happens when new bond to a more electronegative atom occurs or when a double bond is broken between a carbon and a less electronegative atom. A simplified to say this is in organic chemistry a reduction is more bonds to hydrogen and oxidation is more bonds to oxygen often.
Oxacyclopropane Synthesis by Peroxycarboxylic Acid
One way to oxidized a double bond is to produce an oxacyclopropane ring. Oxacyclopropane rings, also called epoxide rings, are useful reagents that may be opened by further reaction to form anti vicinal diols. One way to synthesize oxacyclopropane rings is through the reaction of an alkene with peroxycarboxylic acid . Oxacyclopropane synthesis by peroxycarboxylic acid requires an alkene and a peroxycarboxylic acid as well as an appropriate solvent. The peroxycarboxylic acid has the unique property of having an electropositive oxygen atom on the COOH group. The reaction is initiated by the electrophilic oxygen atom reacting with the nucleophilic carbon-carbon double bond. The mechanism involves a concerted reaction with a four-part, circular transition state. The result is that the originally electropositive oxygen atom ends up in the oxacyclopropane ring and the COOH group becomes COH.
Mechanism
Peroxycarboxylic acids are generally unstable. An exception is meta-chloroperoxybenzoic acid , shown in the mechanism above. Often abbreviated MCPBA, it is a stable crystalline solid. Consequently, MCPBA is popular for laboratory use. However, MCPBA can be explosive under some conditions.
Peroxycarboxylic acids are sometimes replaced in industrial applications by monoperphthalic acid, or the monoperoxyphthalate ion bound to magnesium, which gives magnesium monoperoxyphthalate (MMPP). In either case, a nonaqueous solvent such as chloroform , ether , acetone , or dioxane is used. This is because in an aqueous medium with any acid or base catalyst present, the epoxide ring is hydrolyzed to form a vicinal diol , a molecule with two OH groups on neighboring carbons. (For more explanation of how this reaction leads to vicinal diols, see below.) However, in a nonaqueous solvent, the hydrolysis is prevented and the epoxide ring can be isolated as the product. Reaction yields from this reaction are usually about 75%. The reaction rate is affected by the nature of the alkene, with more nucleophilic double bonds resulting in faster reactions.
Example 8.7.1
Since the transfer of oxygen is to the same side of the double bond, the resulting oxacyclopropane ring will have the same stereochemistry as the starting alkene. A good way to think of this is that the alkene is rotated so that some constituents are coming forward and some are behind. Then, the oxygen is inserted on top. (See the product of the above reaction.) One way the epoxide ring can be opened is by an acid catalyzed oxidation-hydrolysis. Oxidation-hydrolysis gives a vicinal diol , a molecule with OH groups on neighboring carbons. For this reaction, the dihydroxylation is anti since, due to steric hindrance, the ring is attacked from the side opposite the existing oxygen atom. Thus, if the starting alkene is trans, the resulting vicinal diol will have one (S ) and one ( R ) stereocenter . But, if the starting alkene is cis, the resulting vicinal diol will have a racemic mixture of ( S , S ) and ( R , R ) enantiomers .
Epoxidation exercises
1. Predict the product of the reaction of cis-2-hexene with MCPBA (meta-chloroperoxybenzoic acid)
a) in acetone solvent.
b) in an aqueous medium with acid or base catalyst present.
2. Predict the product of the reaction of trans-2-pentene with magnesium monoperoxyphthalate (MMPP) in a chloroform solvent.
3. Predict the product of the reaction of trans-3-hexene with MCPBA in ether solvent.
4. Predict the reaction of propene with MCPBA.
a) in acetone solvent
b) after aqueous work-up.
5. Predict the reaction of cis-2-butene in chloroform solvent.
- Answers
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1. a) Cis -2-methyl-3-propyloxacyclopropane
b) Racemic (2 R ,3 R )-2,3-hexanediol and (2 S ,3 S )-2,3-hexanediol
2. Trans -3-ethyl-2-methyloxacyclopropane.
3. Trans -3,4-diethyloxacyclopropane.
4. a) 2-methyl-oxacyclopropane
b) Racemic (2 S )-1,2-propandiol and (2 R )-1,2-propanediol
5. Cis -2,3-dimethyloxacyclopropane
Anti Dihydroxylation
Epoxides may be cleaved by aqueous acid to give glycols that are often diastereomeric with those prepared by the syn-hydroxylation reaction described above. Proton transfer from the acid catalyst generates the conjugate acid of the epoxide, which is attacked by nucleophiles such as water in the same way that the cyclic bromonium ion described above undergoes reaction. The result is anti-hydroxylation of the double bond, in contrast to the syn-stereoselectivity of the earlier method. In the following equation this procedure is illustrated for a cis-disubstituted epoxide, which, of course, could be prepared from the corresponding cis-alkene. This hydration of an epoxide does not change the oxidation state of any atoms or groups.
Syn Dihydroxylation
Osmium tetroxide oxidizes alkenes to give glycols through syn addition. A glycol, also known as a vicinal diol, is a compound with two -OH groups on adjacent carbons.
Introduction
The reaction with \(OsO_4\) is a concerted process that has a cyclic intermediate and no rearrangements. Vicinal syn dihydroxylation complements the epoxide-hydrolysis sequence which constitutes an anti dihydroxylation of an alkene. When an alkene reacts with osmium tetroxide, stereocenters can form in the glycol product. Cis alkenes give meso products and trans alkenes give racemic mixtures .
\(OsO_4\) is formed slowly when osmium powder reacts with gasoues \(O_2\) at ambient temperature. Reaction of bulk solid requires heating to 400 °C:
\[\ce{Os(s) + 2O2(g) \rightarrow OS_4} \nonumber \]
Since Osmium tetroxide is expensive and highly toxic, the reaction with alkenes has been modified. Catalytic amounts of \(\ce{OsO4}\) and stoichiometric amounts of an oxidizing agent such as hydrogen peroxide are now used to eliminate some hazards. Also, an older reagent that was used instead of \(\ce{OsO4}\) was potassium permanganate, \(KMnO_4\). Although syn diols will result from the reaction of \(\ce{KMnO4}\) and an alkene, potassium permanganate is less useful since it gives poor yields of the product because of overoxidation .
Mechanism
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Electrophilic attack on the alkene
- Pi bond of the alkene acts as the nucleophile and reacts with osmium (VIII) tetroxide (OsO 4 )
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2 electrons from the double bond flows toward the osmium metal
- In the process, 3 electron pairs move simultaneously
- Cyclic ester with Os (VI) is produced
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Reduction
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H
2
S reduces the cyclic ester
- NaHSO 4 with H 2 O may be used
- Forms the syn-1,2-diol (glycol)
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H
2
S reduces the cyclic ester
Example: Dihydroxylation of 1-ethyl-1-cycloheptene
Hydroxylation of alkenes
Dihydroxylated products (glycols) are obtained by reaction with aqueous potassium permanganate (pH > 8) or osmium tetroxide in pyridine solution. Both reactions appear to proceed by the same mechanism (shown below); the metallocyclic intermediate may be isolated in the osmium reaction. In basic solution the purple permanganate anion is reduced to the green manganate ion, providing a nice color test for the double bond functional group. From the mechanism shown here we would expect syn-stereoselectivity in the bonding to oxygen, and regioselectivity is not an issue.
When viewed in context with the previously discussed addition reactions, the hydroxylation reaction might seem implausible. Permanganate and osmium tetroxide have similar configurations, in which the metal atom occupies the center of a tetrahedral grouping of negatively charged oxygen atoms. How, then, would such a species interact with the nucleophilic pi-electrons of a double bond? A possible explanation is that an empty d-orbital of the electrophilic metal atom extends well beyond the surrounding oxygen atoms and initiates electron transfer from the double bond to the metal, in much the same fashion noted above for platinum. Back-bonding of the nucleophilic oxygens to the antibonding π*-orbital completes this interaction. The result is formation of a metallocyclic intermediate, as shown above.
Chemical Highlight
Antitumor drugs have been formed by using dihydroxylation. This method has been applied to the enantioselective synthesis of ovalicin, which is a class of fungal-derived products called antiangiogenesis agents. These antitumor products can cut off the blood supply to solid tumors. A derivative of ovalicin, TNP-470, is chemically stable, nontoxic, and noninflammatory. TNP-470 has been used in research to determine its effectiveness in treating cancer of the breast, brain, cervix, liver, and prostate.
Dihydroxylation Exercises
1. Give the major product.
2. What is the product in the dihydroxylation of (Z)-3-hexene?
3. What is the product in the dihydroxylation of (E)-3-hexene?
4. Draw the intermediate of this reaction.
5. Fill in the missing reactants, reagents, and product.
- Answer s
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1. A syn-1,2-ethanediol is formed. There is no stereocenter in this particular reaction. The OH groups are on the same side.
2. Meso-3,4-hexanediol is formed. There are 2 stereocenters in this reaction.
3. A racemic mixture of 3,4-hexanediol is formed. There are 2 stereocenters in both products.
4. A cyclic osmic ester is formed.
5. The Diels-Alder cycloaddition reaction is needed in the first box to form the cyclohexene. The second box needs a reagent to reduce the intermediate cyclic ester (not shown). The third box has the product: 1,2-cyclohexanediol.
References
- Dehestani, Ahmad et al. (2005). Ligand-assisted reduction of osmium tetroxide with molecular hydrogen via a [3+2] mechanism. Journal of the American Chemical Society, 2005, 127 (10), 3423-3432.
- Sorrell, Thomas, N. Organic Chemistry . New York: University Science Books, 2006.
- Vollhardt, Peter, and Neil E. Schore. Organic Chemistry: Structure and Function . 5th Edition. New York: W. H. Freeman & Company, 2007.


15.9A: Overview of the Parathyroid Glands
The parathyroid glands are small endocrine glands in the neck that produce parathyroid hormone.
- Describe the location and function of the parathyroid glands
Key Points
- The parathyroid glands are four or more small glands, about the size of a grain of rice, located on the posterior surface of the thyroid gland.
- The major function of the parathyroid glands is to maintain the body’s calcium level within a very narrow range, so the nervous and muscular systems can function properly.
Key Terms
- calcitonin : A hormone that is produced primarily by the parafollicular cells of the thyroid. It acts to reduce blood calcium (Ca2+), opposing the effects of parathyroid hormone.
- parathyroid gland : One of four endocrine glands situated in the neck, usually on the posterior surface of the thyroid gland, that produce parathyroid hormone.
- parathyroid hormone : A hormone produced by the parathyroid gland that acts to increase blood calcium levels by stimulating osteoclasts to release calcium from the bone.
The parathyroid glands are small endocrine glands —approximately the size of a grain of rice—in the neck that produce parathyroid hormone. Humans usually have four parathyroid glands, which are usually located on the posterior surface of the thyroid gland, or, in rare cases, within the thyroid gland itself or in the chest.
Parathyroid gland : The parathyroid gland in relation to the thyroid gland. They are located on the posterior surface of the lobes.
The two parathyroid glands on each side that are positioned higher are called the superior parathyroid glands, while the lower two are called the inferior parathyroid glands. Occasionally, some individuals may have six, eight, or even more parathyroid glands.
Parathyroid glands control the amount of calcium in the blood and within the bones. The major function of the parathyroid glands is to maintain the body’s calcium level within a very narrow range, so that the nervous and muscular systems can function properly. When blood calcium levels drop below a certain point, calcium-sensing receptors in the parathyroid gland are activated to release
parathyroid hormone (PTH) into the blood.
PTH modulates calcium and phosphate homeostasis, as well as bone physiology. PTH has effects antagonistic to those of calcitonin by increasing blood calcium levels by stimulating osteoclasts to break down bone and release calcium. PTH also increases gastrointestinal calcium absorption by activating vitamin D, and promotes calcium conservation by re-absorption in the kidneys.


9.4H: Dependency Theories
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Dependency theory states that colonialism and neocolonialism have created unequal economic relations between poor and wealthy countries.
Learning Objectives
- Explain malnourishment and hunger in the “third world” through dependency theory
Key Points
- In the past, colonialism allowed wealthy countries to plunder their colonies for material benefits—raw materials like rubber, sugar, and slave labor.
- Today, poor countries have taken enormous loans from wealthy countries in order to stay afloat. Paying off the compound interest from this debt prevents them from investing resources into their own country.
- Foreign trade gets in the way of local governments’ ability to improve the living conditions of their people by encouraging the export of food and other raw materials to wealthy consumer markets.
Key Terms
- foreign trade : The exchange of capital, goods, and services across international borders or territories.
- foreign debt : A debt that a country, an organization in a country, or a resident individual in a country owes to those in other countries.
- neocolonialism : The control or domination by a powerful country over weaker ones (especially former colonies) by the use of economic pressure, political suppression, and cultural dominance.
- dependency ratio : an age-population measurement of those typically not in the labor force (the dependent part) and those typically in the labor force (the productive part)
Dependency theories propose that colonialism and neocolonialism —continuing economic dependence on and exploitation of former colonial countries—are the main causes global poverty. Countries have developed at an uneven rate because wealthy countries have exploited poor countries in the past and continue to do so today through foreign debt and foreign trade.
Historical Dependency
Historically, wealthy nations have taken a great quantity of materials from poor countries, such as minerals and metals necessary to make automobiles, weapons, and jewelry. Large amounts of agricultural products that can only be grown in the hot climates of the poor countries, such as coffee, tea, sugar, and cocoa, have been exported to and manufactured in the wealthy countries. Wealthy countries would not be as rich as they are today if they did not have these materials. Wealthy countries increased their own profits by organizing cheap labor through slavery.
King Leopold II, for example, who was King of Belgium from 1865-1909, forced hundreds of thousands of men, women, and children to work as slaves in the Democratic Republic of Congo. The invention of the bicycle tire in the 1890s and later the automobile tire meant that rubber was in high demand; wild rubber vines were widespread in the Congo, earning Leopold millions. The Democratic Republic of Congo is still suffering from the plunder of natural resources, torture, and killing that was endured during Leopold’s reign.
Modern Dependency
Today, poor countries are trapped by large debts which prevent them from developing. For example, between 1970 and 2002, the continent of Africa received $540 billion in loans from wealthy nations—through the World Bank and IMF. African countries have paid back $550 billion of their debt but they still owe $295 billion. The difference is the result of compound interest. Countries cannot focus on economic or human development when they are constantly paying off debt; these countries will continue to remain undeveloped. Dependency theorists believe large economic aid is not necessarily the key to reducing poverty and developing, but rather debt relief may be a more effective step.
In addition, foreign trade and business often mitigate local governments’ ability to improve the living conditions of their people. This trade often comes in the form of transnational corporations (TNCs). The governments of poor countries invite these TNCs to invest in their country with the hope of developing the country and bringing material benefit to the people. However, workers’ time and energy are often poured into producing goods that they themselves will not consume. For example, some of the land in Cape Verde could be planted and harvested to feed local people, but it is planted instead with cash crops for foreign exchange. Fresh produce is regularly sold or changed to a nonperishable type such as tuna canned for export rather than consumed by the population.
Malnutrition and Dependency
Widespread malnutrition is one of the effects of this foreign dependency. This is common around the globe. Brazil is the second largest exporter of agricultural products, but 50 percent of its population is malnourished. Although Ethiopia has one of the largest populations of cattle in Africa, much of the population suffers from malnutrition and the government continues to export large numbers of cattle to the Middle East. Even during the peak of the infamous 1985 famine, the government was sending dried meat to Egypt.
Through unequal economic relations with wealthy countries in the form of continued debts and foreign trade, poor countries continue to be dependent and unable to tap into their full potential for development.


11.7F: Primary and Secondary Antibody Responses
- Generalize the role of the innate and adaptive immune system in regards to antibody response
The immune system is a system of biological structures and processes within an organism that protects against disease. To function properly, an immune system must detect a wide variety of agents, from viruses to parasitic worms, and distinguish them from the organism’s own healthy tissue. Pathogens can rapidly evolve and adapt to avoid detection and neutralization by the immune system. As a result, multiple defense mechanisms have also evolved to recognize and neutralize pathogens. Even simple unicellular organisms such as bacteria possess a rudimentary immune system, in the form of enzymes that protect against bacteriophage infections. Other basic immune mechanisms evolved in ancient eukaryotes and remain in their modern descendants, such as plants and insects. These mechanisms include phagocytosis, antimicrobial peptides called defensins, and the complement system. Jawed vertebrates, including humans, have even more sophisticated defense mechanisms, including the ability to adapt over time to recognize specific pathogens more efficiently. Adaptive (or acquired) immunity creates immunological memory after an initial response to a specific pathogen, leading to an enhanced response to subsequent encounters with that same pathogen. This process of acquired immunity is the basis of vaccination.
Disorders of the immune system can result in autoimmune diseases, inflammatory diseases and cancer. Immunodeficiency occurs when the immune system is less active than normal, resulting in recurring and life-threatening infections. In humans, immunodeficiency can either be the result of a genetic disease such as severe combined immunodeficiency, acquired conditions such as HIV/AIDS, or the use of immunosuppressive medication. In contrast, autoimmunity results from a hyperactive immune system attacking normal tissues as if they were foreign organisms. Common autoimmune diseases include Hashimoto’s thyroiditis, rheumatoid arthritis, diabetes mellitus type 1, and systemic lupus erythematosus. Immunology covers the study of all aspects of the immune system.
The immune system protects organisms from infection with layered defenses of increasing specificity. In simple terms, physical barriers prevent pathogens such as bacteria and viruses from entering the organism. If a pathogen breaches these barriers, the innate immune system provides an immediate, but non-specific response. Innate immune systems are found in all plants and animals. If pathogens successfully evade the innate response, vertebrates possess a second layer of protection, the adaptive immune system, which is activated by the innate response. Here, the immune system adapts its response during an infection to improve its recognition of the pathogen. This improved response is then retained after the pathogen has been eliminated, in the form of an immunological memory, and allows the adaptive immune system to mount faster and stronger attacks each time this pathogen is encountered. Both innate and adaptive immunity depend on the ability of the immune system to distinguish between self and non- self molecules. In immunology, self molecules are those components of an organism’s body that can be distinguished from foreign substances by the immune system. Conversely, non-self molecules are those recognized as foreign molecules. One class of non-self molecules are called antigens (short for antibody generators) and are defined as substances that bind to specific immune receptors and elicit an immune response.
When B cells and T cells are first activated by a pathogen, memory B-cells and T- cells develop. Throughout the lifetime of an animal these memory cells will “remember” each specific pathogen encountered, and are able to mount a strong response if the pathogen is detected again. This type of immunity is both active and adaptive because the body’s immune system prepares itself for future challenges. Active immunity often involves both the cell-mediated and humoral aspects of immunity as well as input from the innate immune system. The innate system is present from birth and protects an individual from pathogens regardless of experiences, whereas adaptive immunity arises only after an infection or immunization and hence is “acquired” during life.
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- File:Antibody.svg - Wikipedia, the free encyclopedia. Provided by : Wikipedia. Located at : en.Wikipedia.org/w/index.php?...ody.svg&page=1 . License : Public Domain: No Known Copyright
- VDJ recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:VD...ombination.png . License : Public Domain: No Known Copyright
- B cell. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/B_cell%...ent_of_B_cells . License : CC BY-SA: Attribution-ShareAlike
- Clonal selection. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Clonal_selection . License : CC BY-SA: Attribution-ShareAlike
- clonal selection. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/clonal%20selection . License : CC BY-SA: Attribution-ShareAlike
- clone. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/clone . License : CC BY-SA: Attribution-ShareAlike
- Antibody%252520je2. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Antibody_je2.png . License : Public Domain: No Known Copyright
- IgM%252520IgE%252520scheme. Provided by : Wikimedia. Located at : commons.wikimedia.org/wiki/Fi...IgE_scheme.png . License : CC BY-SA: Attribution-ShareAlike
- File:Antibody.svg - Wikipedia, the free encyclopedia. Provided by : Wikipedia. Located at : en.Wikipedia.org/w/index.php?...ody.svg&page=1 . License : Public Domain: No Known Copyright
- VDJ recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:VD...ombination.png . License : Public Domain: No Known Copyright
- Hematopoiesis (human) diagram. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:He...n)_diagram.png . License : CC BY-SA: Attribution-ShareAlike
- Clonal selection. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Cl..._selection.svg . License : CC BY-SA: Attribution-ShareAlike
- class switch recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/class%2...0recombination . License : CC BY-SA: Attribution-ShareAlike
- Antibody. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Antibody%23Isotypes . License : CC BY-SA: Attribution-ShareAlike
- Isotype switching. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Isotype_switching . License : CC BY-SA: Attribution-ShareAlike
- isotype. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/isotype . License : CC BY-SA: Attribution-ShareAlike
- Antibody%252520je2. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Antibody_je2.png . License : Public Domain: No Known Copyright
- IgM%252520IgE%252520scheme. Provided by : Wikimedia. Located at : commons.wikimedia.org/wiki/Fi...IgE_scheme.png . License : CC BY-SA: Attribution-ShareAlike
- File:Antibody.svg - Wikipedia, the free encyclopedia. Provided by : Wikipedia. Located at : en.Wikipedia.org/w/index.php?...ody.svg&page=1 . License : Public Domain: No Known Copyright
- VDJ recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:VD...ombination.png . License : Public Domain: No Known Copyright
- Hematopoiesis (human) diagram. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:He...n)_diagram.png . License : CC BY-SA: Attribution-ShareAlike
- Clonal selection. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Cl..._selection.svg . License : CC BY-SA: Attribution-ShareAlike
- Class switch recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Cl...ombination.png . License : Public Domain: No Known Copyright
- Paratope. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Paratope . License : CC BY-SA: Attribution-ShareAlike
- Memory B cell. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Memory_B_cell . License : CC BY-SA: Attribution-ShareAlike
- Boundless. Provided by : Boundless Learning. Located at : www.boundless.com//microbiolo...on/memory-cell . License : CC BY-SA: Attribution-ShareAlike
- paratope. Provided by : Wiktionary. Located at : en.wiktionary.org/wiki/paratope . License : CC BY-SA: Attribution-ShareAlike
- Antibody%252520je2. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Antibody_je2.png . License : Public Domain: No Known Copyright
- IgM%252520IgE%252520scheme. Provided by : Wikimedia. Located at : commons.wikimedia.org/wiki/Fi...IgE_scheme.png . License : CC BY-SA: Attribution-ShareAlike
- File:Antibody.svg - Wikipedia, the free encyclopedia. Provided by : Wikipedia. Located at : en.Wikipedia.org/w/index.php?...ody.svg&page=1 . License : Public Domain: No Known Copyright
- VDJ recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:VD...ombination.png . License : Public Domain: No Known Copyright
- Hematopoiesis (human) diagram. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Hematopoiesis_(human)_diagram.png . License : CC BY-SA: Attribution-ShareAlike
- Clonal selection. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Clonal_selection.svg . License : CC BY-SA: Attribution-ShareAlike
- Class switch recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Class_switch_recombination.png . License : Public Domain: No Known Copyright
- File:Original antigenic sin.svg - Wikipedia, the free encyclopedia. Provided by : Wikipedia. Located at : en.Wikipedia.org/w/index.php?...sin.svg&page=1 . License : CC BY-SA: Attribution-ShareAlike
- Primary antibody. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Primary_antibody . License : CC BY-SA: Attribution-ShareAlike
- Antibodies. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Antibodies . License : CC BY-SA: Attribution-ShareAlike
- Immune response. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Immune_response . License : CC BY-SA: Attribution-ShareAlike
- Memory B cell. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Memory_...C_and_epitopes . License : CC BY-SA: Attribution-ShareAlike
- adaptive immunity. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/adaptive%20immunity . License : CC BY-SA: Attribution-ShareAlike
- Memory B cell. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/Memory_...nse_and_memory . License : CC BY-SA: Attribution-ShareAlike
- Antibody%252520je2. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Antibody_je2.png . License : Public Domain: No Known Copyright
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- File:Antibody.svg - Wikipedia, the free encyclopedia. Provided by : Wikipedia. Located at : en.Wikipedia.org/w/index.php?...ody.svg&page=1 . License : Public Domain: No Known Copyright
- VDJ recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:VD...ombination.png . License : Public Domain: No Known Copyright
- Hematopoiesis (human) diagram. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Hematopoiesis_(human)_diagram.png . License : CC BY-SA: Attribution-ShareAlike
- Clonal selection. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Clonal_selection.svg . License : CC BY-SA: Attribution-ShareAlike
- Class switch recombination. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Class_switch_recombination.png . License : Public Domain: No Known Copyright
- File:Original antigenic sin.svg - Wikipedia, the free encyclopedia. Provided by : Wikipedia. Located at : en.Wikipedia.org/w/index.php?title=File:Original_antigenic_sin.svg&page=1 . License : CC BY-SA: Attribution-ShareAlike
- Immune response. Provided by : Wikipedia. Located at : en.Wikipedia.org/wiki/File:Immune_response.jpg . License : Public Domain: No Known Copyright
Key Points
- When B cells and T cells are first activated by a pathogen, memory B-cells and T- cells develop.
- Throughout the lifetime of an animal these memory cells will “remember” each specific pathogen encountered, and are able to mount a strong response if the pathogen is detected again. This type of immunity is both active and adaptive.
- Active immunity often involves both the cell-mediated and humoral aspects of immunity as well as input from the innate immune system.
Key Terms
- secondary response : the immune response occurring on second and subsequent exposures to an antigen, with a stronger response to a lesser amount of antigen, and a shorter lag time compared to the primary immune response
- primary response : the immune response occurring on the first exposure to an antigen, with specific antibodies appearing in the blood after a multiple day latent period
- adaptive immunity : the components of the immune system that adapt themselves to each new disease encountered and are able to generate pathogen-specific immunity.


1.7: Density and specific gravity measurements
Density
Density is the mass-to-volume ratio of a substance.
Density is a physical characteristic of matter. Each substance has a characteristic density that can be used as one hint in identifying a substance.
Gases have very low density, usually expressed in g/L. For example, air density is around 1.224 g/L at sea level and 15 o C. The density of liquids and solids is usually expressed in g/mL. For example, the density of water at 4 o C is 1.00 g/mL.
Objects that are less dense than water float, and the denser objects than water sink in the water. For example, oil is less dense than water and floats on water. Metals are denser than water and sink in water. The density of some common substances is listed in Table 1
| Substance | Density (g/mL) |
|---|---|
| hydrogen | 0.000089 |
| carbon dioxide | 0.0019 |
| ethyl alcohol | 0.7893 |
| water | 1.00 |
| magnesium | 1.74 |
| table salt | 2.16 |
| aluminum | 2.70 |
| iron | 7.86 |
| copper | 8.92 |
| silver | 10.50 |
| lead | 11.34 |
| mercury | 13.59 |
| gold | 19.30 |
Density measurement
Density (d) is calculated from the mass (m) and volume (V) of a substance by the formula:
\[d = \frac{m}{V}\nonumber\]
Mass is usually measured using an analytical balance. The volume of liquids can be measured using a graduated cylinder, pipet, or density bottle. The volume of regular solids can be calculated from the geometric parameters. For example, the volume of a rectangle is equal to length x width x height. The volume of a cube is equal to the edge length cubed.
The volume of an irregular shaped sold is usually measured because the substances that are denser than water sink and displace an equal amount of water. Fig. 1.7.1 illustrates the density measurement of an irregular-shaped solid object that sinks in water, as explained in the following example.
Wwhat the density of the object in Fig. 1.7.1?
Soution
the mass (m) of the object on balance is 1000.00 g. The volume of the object is equal to the volume of the water displaced by the object, which is 225.0 mL – 100.0 mL = 125.0 mL.
\begin{equation}
d=\frac{m}{V}=\frac{1000.00 \mathrm{~g}}{125.0 \mathrm{~mL}}=8.000 \frac{\mathrm{g}}{\mathrm{ml}}\nonumber
\end{equation}
Most of the time, Calculators give more significant numbers and sometimes less than needed; both need correction. In example 1.7.1, the calculator displays 8, i.e., one significant figure, but three zeros are added to make four significant figures.
Bone density and osteoporosis
Osteoporosis is a bone disease associated with decreased bone density, particularly in older adults. Bones always lose and gain calcium, magnesium, and phosphate. In childhood, the bones build faster than decay, but in old age, the process reverses, and the bones start to thin, loos strength, and become more prone to fracture, as illustrated in Fig. 1.7.2. Hormonal changes, diseases, and some medications contribute to bone thinning. Severe loss of bone density is called osteoporosis.
Specific gravity
Specific gravity is the ratio of the object's density to the density of water, i.e.:
\begin{equation}
\text { Specific gravity }=\frac{\text { Density of an object }}{\text { Density of water }}\nonumber
\end{equation}
Specific gravity is the ratio of the object's density to the density of water, i.e.:
\begin{equation}
\text { Specific gravity }=\frac{\text { Density of an object }}{\text { Density of water }}\nonumber
\end{equation}
The units cancel out in the ratio. Therefore, the specific gravity is a unitless number. The density of water is 1.0 g/mL at room temperature, so the specific gravity is equal to the density of the object expressed without a unit.
When substances dissolve in water, the density of the solution is usually different from pure water. For example, the density of whole blood for humans is ~1.060 g/mL. The density of urine varies in the range of 1.0050 g/mL to 1.030 g/mL. Both the blood and urine have dissolved substances in water that increase the density from that of pure water. Both high and low density or specific gravity than the normal range of urine indicates medical problems. An increase in the specific gravity of urine indicates that it is due to an increase in the solutes caused by dehydration, diarrhea, or infection. Similarly, a decrease in solute concentration decreases the specific gravity of urine, which indicates medical problems like renal failure.
Specific gravity measurement
The specific gravity is usually measured using an instrument called a hydrometer. The hydrometer partially submerges in the liquid sample, and the reading on the scale at the air-water junction point is recorded, as illustrated in Fig. 1.7.3.


Describe stages of language development during infancy
Compare theories of language development in toddlers
Given the remarkable complexity of a language, one might expect that mastering a language would be an especially arduous task; indeed, for those of us trying to learn a second language as adults, this might seem to be true. However, young children master language very quickly with relative ease. B. F. Skinner (1957) proposed that language is learned through reinforcement. Noam Chomsky (1965) criticized this behaviorist approach, asserting instead that the mechanisms underlying language acquisition are biologically determined. The use of language develops in the absence of formal instruction and appears to follow a very similar pattern in children from vastly different cultures and backgrounds. It would seem, therefore, that we are born with a biological predisposition to acquire a language (Chomsky, 1965; Fernández & Cairns, 2011). Moreover, it appears that there is a critical period for language acquisition, such that this proficiency at acquiring language is maximal early in life; generally, as people age, the ease with which they acquire and master new languages diminishes (Johnson & Newport, 1989; Lenneberg, 1967; Singleton, 1995).
Children begin to learn about language from a very early age (Table 1). In fact, it appears that this is occurring even before we are born. Newborns show a preference for their mother’s voice and appear to be able to discriminate between the language spoken by their mother and other languages. Babies are also attuned to the languages being used around them and show preferences for videos of faces that are moving in synchrony with the audio of spoken language versus videos that do not synchronize with the audio (Blossom & Morgan, 2006; Pickens, 1994; Spelke & Cortelyou, 1981).
Table 1. Stages of Language and Communication Development
Stage
Age
Developmental Language and Communication
1
0–3 months
Reflexive communication
2
3–8 months
Reflexive communication; interest in others
3
8–12 months
Intentional communication; sociability
4
12–18 months
First words
5
18–24 months
Simple sentences of two words
6
2–3 years
Sentences of three or more words
7
3–5 years
Complex sentences; has conversations
Each language has its own set of
phonemes
that are used to generate
morphemes
, words, and so on. Babies can discriminate among the sounds that make up a language (for example, they can tell the difference between the “s” in vision and the “ss” in fission); early on, they can differentiate between the sounds of all human languages, even those that do not occur in the languages that are used in their environments. However, by the time that they are about 1 year old, they can only discriminate among those phonemes that are used in the language or languages in their environments (Jensen, 2011; Werker & Lalonde, 1988; Werker & Tees, 1984).
Watch It
This video explains some of the research surrounding language acquisition in babies, particularly those learning a second language.
Do newborns communicate? Certainly, they do. They do not, however, communicate with the use of language. Instead, they communicate their thoughts and needs with body posture (being relaxed or still), gestures, cries, and facial expressions. A person who spends adequate time with an infant can learn which cries indicate pain and which ones indicate hunger, discomfort, or frustration.
Intentional Vocalizations
Infants begin to vocalize and repeat vocalizations within the first couple of months of life. That gurgling, musical vocalization called cooing can serve as a source of entertainment to an infant who has been laid down for a nap or seated in a carrier on a car ride. Cooing serves as practice for vocalization. It also allows the infant to hear the sound of their own voice and try to repeat sounds that are entertaining. Infants also begin to learn the pace and pause of conversation as they alternate their vocalization with that of someone else and then take their turn again when the other person’s vocalization has stopped. Cooing initially involves making vowel sounds like “oooo.” Later, as the baby moves into babbling (see below), consonants are added to vocalizations such as “nananananana.”
Babbling and Gesturing
Between 6 and 9 months, infants begin making even more elaborate vocalizations that include the sounds required for any language. Guttural sounds, clicks, consonants, and vowel sounds stand ready to equip the child with the ability to repeat whatever sounds are characteristic of the language heard. These babies repeat certain syllables (ma-ma-ma, da-da-da, ba-ba-ba), a vocalization called
babbling
because of the way it sounds. Eventually, these sounds will no longer be used as the infant grows more accustomed to a particular language. Deaf babies also use gestures to communicate wants, reactions, and feelings. Because gesturing seems to be easier than vocalization for some toddlers, sign language is sometimes taught to enhance one’s ability to communicate by making use of the ease of gesturing. The rhythm and pattern of language are used when deaf babies sign just as when hearing babies babble.
At around ten months of age, infants can understand more than they can say. You may have experienced this phenomenon as well if you have ever tried to learn a second language. You may have been able to follow a conversation more easily than to contribute to it.
Children begin using their first words at about 12 or 13 months of age and may use partial words to convey thoughts at even younger ages. These one-word expressions are referred to as holophrasic speech (
holophrase
). For example, the child may say “ju” for the word “juice” and use this sound when referring to a bottle. The listener must interpret the meaning of the holophrase. When this is someone who has spent time with the child, interpretation is not too difficult. They know that “ju” means “juice” which means the baby wants some milk! But, someone who has not been around the child will have trouble knowing what is meant. Imagine the parent who exclaims to a friend, “Ezra’s talking all the time now!” The friend hears only “ju da ga” which, the parent explains, means “I want some milk when I go with Daddy.”
Underextension
A child who learns that a word stands for an object may initially think that the word can be used for only that particular object. Only the family’s Irish Setter is a “doggie.” This is referred to as underextension. More often, however, a child may think that a label applies to all objects that are similar to the original object. In overextension, all animals become “doggies,” for example.
First words and cultural influences
First words for English-speaking children tend to be nouns. The child labels objects such as a cup or a ball. In a verb-friendly language such as Chinese, however, children may learn more verbs. This may also be due to the different emphasis given to objects based on culture. Chinese children may be taught to notice action and relationship between objects while children from the United States may be taught to name an object and its qualities (color, texture, size, etc.). These differences can be seen when comparing interpretations of art by older students from China and the United States.
Vocabulary growth spurt
One-year-olds typically have a vocabulary of about 50 words. But by the time they become toddlers, they have a vocabulary of about 200 words and begin putting those words together in telegraphic speech (short phrases). This language growth spurt is called the
naming explosion
because many early words are nouns (persons, places, or things).
Two-word sentences and telegraphic speech
Words are soon combined and 18-month-old toddlers can express themselves further by using phrases such as “baby bye-bye” or “doggie pretty.” Words needed to convey messages are used, but the articles and other parts of speech necessary for grammatical correctness are not yet included. These expressions sound like a telegraph (or perhaps a better analogy today would be that they read like a text message) where unnecessary words are not used. “Give baby ball” is used rather than “Give the baby the ball.” Or a text message of “Send money now!” rather than “Dear Mother. I really need some money to take care of my expenses.” You get the idea.
Child-directed speech
Why is a horse a “horsie”? Have you ever wondered why adults tend to use “baby talk” or that sing-song type of intonation and exaggeration used when talking to children? This represents a universal tendency and is known as child-directed speech or motherese or parentese. It involves exaggerating the vowel and consonant sounds, using a high-pitched voice, and delivering the phrase with great facial expression. Why is this done? It may be in order to clearly articulate the sounds of a word so that the child can hear the sounds involved. Or it may be because when this type of speech is used, the infant pays more attention to the speaker and this sets up a pattern of interaction in which the speaker and listener are in tune with one another. When I demonstrate this in class, the students certainly pay attention and look my way. Amazing! It also works in the college classroom!
Watch It
This video examines new research on infant-directed speech.
How is language learned? Each major theory of language development emphasizes different aspects of language learning: that infants’ brains are genetically attuned to language, that infants must be taught, and that infants’ social impulses foster language learning. The first two theories of language development represent two extremes in the level of interaction required for language to occur (Berk, 2007).
Chomsky and the language acquisition device
This theory posits that infants teach themselves and that language learning is genetically programmed. The view is known as
nativism
and was advocated by Noam Chomsky, who suggested that infants are equipped with a neurological construct referred to as the
language acquisition device (LAD)
, which makes infants ready for language. The LAD allows children, as their brains develop, to derive the rules of grammar quickly and effectively from the speech they hear every day. Therefore, language develops as long as the infant is exposed to it. No teaching, training, or reinforcement is required for language to develop. Instead, language learning comes from a particular gene, brain maturation, and the overall human impulse to imitate.
Skinner and reinforcement
This theory is the opposite of Chomsky’s theory because it suggests that infants need to be taught language. This idea arises from behaviorism. Learning theorist, B. F. Skinner, suggested that language develops through the use of reinforcement. Sounds, words, gestures, and phrases are encouraged by following the behavior with attention, words of praise, treats, or anything that increases the likelihood that the behavior will be repeated. This repetition strengthens associations, so infants learn the language faster as parents speak to them often. For example, when a baby says “ma-ma,” the mother smiles and repeats the sound while showing the baby attention. So, “ma-ma” is repeated due to this reinforcement.
Social pragmatics
Another language theory emphasizes the child’s active engagement in learning the language out of a need to communicate. Social impulses foster infant language because humans are social beings and we must communicate because we are dependent on each other for survival. The child seeks information, memorizes terms, imitates the speech heard from others, and learns to conceptualize using words as language is acquired. Tomasello & Herrmann (2010) argue that all human infants, as opposed to chimpanzees, seek to master words and grammar in order to join the social world
[1]
Many would argue that all three of these theories (Chomsky’s argument for nativism, conditioning, and social pragmatics) are important for fostering the acquisition of language (Berger, 2004).
an infant’s repetition of certain syllables, such as ba-ba-ba, that begins when babies are between 6 and 9 months old
holophrase
a single word that is used to express a complete, meaningful thought
language acquisition device (LAD)
Chomsky’s term for the hypothesized mental structure that enables humans to learn the language, including the basic aspects of grammar, vocabulary, and intonation
morpheme
the smallest unit of language that conveys some type of meaning
naming explosion
a sudden increase in an infant’s vocabulary, especially in the number of nouns, that begins at about 18 months of age
phoneme
a basic sound unit of a given language
Tomasello, M. & Hermann, E. (2010). Ape and human cognition. Current Directions in Psychological Science, 19(1), 3-8.
<EMAIL_ADDRESS>Contributors and Attributions
CC licensed content, Original
Modification, adaptation, and original content.
Authored by
: Tera Jones for Lumen Learning.
Provided by
: Lumen Learning.
License
:
CC BY: Attribution


14.9: Suggested Resources
14.1 Types of Resources
The Business Journals company profiles: https://www.bizjournals.com/profiles/company
Circleup: http://circleup.com
Exilend: https://www.exilend.com
Fundable: http://fundable.com
Indiegogo: http://indiegogo.com
Kickstarter: http://kickstarter.com
LendingKarma: http://www.lendingkarma.com
LoanBack: http://loanback.com
NewsLink: http://www.newslink.org
Society of Human Resources Management: http://shrm.org
US Small Business Administration: https://www.sba.gov/
US Securities and Exchange Commission Regulatory Actions: https://www.sec.gov/rules.shtml
Trade Show News Network: www.tsnn.com
US Census Bureau: http://www.census.gov
Copyright Office: https://www.copyright.gov/
US Chamber of Commerce: https://www.uschamber.com/
US Patent and Trademark Office: https://www.uspto.gov/
ZimpleMoney: http://www.zimplemoney.com
SEC Information on crowdfunding portals: https://www.sec.gov/divisions/market...ationguide.htm
Link to SEC (FINRA) crowdfunding portals: https://www.finra.org/about/funding-...ls-we-regulate
New York University, Stern School of Business: https://www.stern.nyu.edu/
Link to data on margins by sector: http://pages.stern.nyu.edu/~adamodar...le/margin.html
Loopnet: www.loopnet.com/
Bizstats: www.bizstats.com/
14.2 Using the PEST Framework to Assess Resource Needs
SBA calculation of startup costs: https://www.sba.gov/business-guide/p...ction-header-6
US Department of Labor: https://www.dol.gov/general/topic/st.../wagesearnings
14.3 Managing Resources over the Venture Life Cycle
Referrals and Associations
Tradeshows: www.tsnn.com/
Industry research publications: http://www.newslink.org
National Association of Women Business Owners: https://www.nawbo.org/
University and Organizational Resources
Small Business Development Centers: https://www.sba.gov/offices/headquar...osbdc/about-us
New York University, Stern School of Business: https://www.stern.nyu.edu/
Governmental and Other Agencies:
/www.bls.gov
https://www.ready.gov/business/imple...ation/resource


11.1: Prelude to Angular Momentum
Angular momentum is the rotational counterpart of linear momentum. Any massive object that rotates about an axis carries angular momentum, including rotating flywheels, planets, stars, hurricanes, tornadoes, whirlpools, and so on. The helicopter shown below can be used to illustrate the concept of angular momentum. The lift blades spin about a vertical axis through the main body and carry angular momentum. The body of the helicopter tends to rotate in the opposite sense in order to conserve angular momentum. The small rotors at the tail of the aircraft provide a counter thrust against the body to prevent this from happening, and the helicopter stabilizes itself. The concept of conservation of angular momentum is discussed later in this chapter. In the main part of this chapter, we explore the intricacies of angular momentum of rigid bodies such as a top, and also of point particles and systems of particles. But to be complete, we start with a discussion of rolling motion, which builds upon the concepts of the previous chapter.