1.4: Problems
1 . Correct use of a calculator: (a) Calculate \(\frac{74658}{53222+97554}\) on a calculator. [Self-check: The most common mistake results in 97555.40.] (answer check available at lightandmatter.com)
(b) Which would be more like the price of a TV, and which would be more like the price of a house, $\(3.5\times10^5\) or $\(3.5^5\)?
2
. Compute the following things. If they don't make sense because of units, say so.
(a) 3 cm + 5 cm
(b) 1.11 m + 22 cm
(c) 120 miles + 2.0 hours
(d) 120 miles / 2.0 hours
3 . Your backyard has brick walls on both ends. You measure a distance of 23.4 m from the inside of one wall to the inside of the other. Each wall is 29.4 cm thick. How far is it from the outside of one wall to the outside of the other? Pay attention to significant figures.
4 . The speed of light is \(3.0\times10^8\) m/s. Convert this to furlongs per fortnight. A furlong is 220 yards, and a fortnight is 14 days. An inch is 2.54 cm.(answer check available at lightandmatter.com)
5
. Express each of the following quantities in micrograms:
(a) 10 mg, (b) \(10^4\) g, (c) 10 kg, (d) \(100\times10^3\) g, (e) 1000 ng. (answer check available at lightandmatter.com)
6 . (solution in the pdf version of the book) Convert 134 mg to units of kg, writing your answer in scientific notation.
7 . In the last century, the average age of the onset of puberty for girls has decreased by several years. Urban folklore has it that this is because of hormones fed to beef cattle, but it is more likely to be because modern girls have more body fat on the average and possibly because of estrogen-mimicking chemicals in the environment from the breakdown of pesticides. A hamburger from a hormone-implanted steer has about 0.2 ng of estrogen (about double the amount of natural beef). A serving of peas contains about 300 ng of estrogen. An adult woman produces about 0.5 mg of estrogen per day (note the different unit!). (a) How many hamburgers would a girl have to eat in one day to consume as much estrogen as an adult woman's daily production? (b) How many servings of peas? (answer check available at lightandmatter.com)
8 . (solution in the pdf version of the book) The usual definition of the mean (average) of two numbers \(a\) and \(b\) is \((a+b)/2\). This is called the arithmetic mean. The geometric mean, however, is defined as \((ab)^{1/2}\) (i.e., the square root of \(ab\)). For the sake of definiteness, let's say both numbers have units of mass. (a) Compute the arithmetic mean of two numbers that have units of grams. Then convert the numbers to units of kilograms and recompute their mean. Is the answer consistent? (b) Do the same for the geometric mean. (c) If \(a\) and \(b\) both have units of grams, what should we call the units of ab ? Does your answer make sense when you take the square root? (d) Suppose someone proposes to you a third kind of mean, called the superduper mean, defined as \((ab)^{1/3}\). Is this reasonable?
9 . In an article on the SARS epidemic, the May 7, 2003 New York Times discusses conflicting estimates of the disease's incubation period (the average time that elapses from infection to the first symptoms). “The study estimated it to be 6.4 days. But other statistical calculations ... showed that the incubation period could be as long as 14.22 days.” What's wrong here?
10 . The photo shows the corner of a bag of pretzels. What's wrong here?
11 . The distance to the horizon is given by the expression \(\sqrt{2rh}\), where \(r\) is the radius of the Earth, and \(h\) is the observer's height above the Earth's surface. (This can be proved using the Pythagorean theorem.) Show that the units of this expression make sense. (See example 2 on p. 26 for an example of how to do this.) Don't try to prove the result, just check its units.
12 . (solution in the pdf version of the book) (a) Based on the definitions of the sine, cosine, and tangent, what units must they have? (b) A cute formula from trigonometry lets you find any angle of a triangle if you know the lengths of its sides. Using the notation shown in the figure, and letting \(s=(a+b+c)/2\) be half the perimeter, we have
Show that the units of this equation make sense. In other words, check that the units of the right-hand side are the same as your answer to part a of the question.
13 . A physics homework question asks, “If you start from rest and accelerate at 1.54 \(\ \text{m}/\text{s}^2\) for 3.29 s, how far do you travel by the end of that time?” A student answers as follows:
His Aunt Wanda is good with numbers, but has never taken physics. She doesn't know the formula for the distance traveled under constant acceleration over a given amount of time, but she tells her nephew his answer cannot be right. How does she know?
14 . You are looking into a deep well. It is dark, and you cannot see the bottom. You want to find out how deep it is, so you drop a rock in, and you hear a splash 3.0 seconds later. How deep is the well? (answer check available at lightandmatter.com)
15
. You take a trip in your spaceship to another star.  Once you get half-way there, you start decelerating, at the same rate, so that by the time you get there, you have slowed down to zero speed. You see the tourist attractions, and then head home by the same method.
(a) Find a formula for the time, \(T\), required for the round trip, in terms of \(d\), the distance from our sun to the star, and \(a\), the magnitude of the acceleration. Note that the acceleration is not constant over the whole trip, but the trip can be broken up into constant-acceleration parts.
(b) The nearest star to the Earth (other than our own sun) is Proxima Centauri, at a distance of \(d=4\times10^{16}\ \text{m}\). Suppose you use an acceleration of \(a=10\ \text{m}/\text{s}^2\), just enough to compensate for the lack of true gravity and make you feel comfortable. How long does the round trip take, in years?
(c) Using the same numbers for \(d\) and \(a\), find your maximum speed. Compare this to the speed of light, which is \(3.0\times10^8\) \ \textup{m}/\textup{s}. (Later in this course, you will learn that there are some new things going on in physics when one gets close to the speed of light, and that it is impossible to exceed the speed of light. For now, though, just use the simpler ideas you've learned so far.) (answer check available at lightandmatter.com)
16 . You climb half-way up a tree, and drop a rock. Then you climb to the top, and drop another rock. How many times greater is the velocity of the second rock on impact? Explain. (The answer is not two times greater.)
17 . (solution in the pdf version of the book) If the acceleration of gravity on Mars is 1/3 that on Earth, how many times longer does it take for a rock to drop the same distance on Mars? Ignore air resistance.
18 . A person is parachute jumping. During the time between when she leaps out of the plane and when she opens her chute, her altitude is given by an equation of the form
where \(e\) is the base of natural logarithms, and \(b\), \(c\), and \(k\) are constants. Because of air resistance, her velocity does not increase at a steady rate as it would for an object falling in vacuum.
(a) What units would \(b\), \(c\), and \(k\) have to have for the equation to make sense?
(b) Find the person's velocity, \(v\), as a function of time. [You will need to use the chain rule, and the fact that \(d(e^x)/dx=e^x\).] (answer check available at lightandmatter.com)
(c) Use your answer from part (b) to get an interpretation of the constant \(c\). [Hint: \(e^{-x}\) approaches zero for large values of \(x\).]
(d) Find the person's acceleration, \(a\), as a function of time.(answer check available at lightandmatter.com)
(e) Use your answer from part (d) to show that if she waits long enough to open her chute, her acceleration will become very small.
19 . (solution in the pdf version of the book) In July 1999, Popular Mechanics carried out tests to find which car sold by a major auto maker could cover a quarter mile (402 meters) in the shortest time, starting from rest. Because the distance is so short, this type of test is designed mainly to favor the car with the greatest acceleration, not the greatest maximum speed (which is irrelevant to the average person). The winner was the Dodge Viper, with a time of 12.08 s. The car's top (and presumably final) speed was 118.51 miles per hour (52.98 \ \textup{m}/\textup{s}). (a) If a car, starting from rest and moving with constant acceleration, covers a quarter mile in this time interval, what is its acceleration? (b) What would be the final speed of a car that covered a quarter mile with the constant acceleration you found in part a? (c) Based on the discrepancy between your answer in part \(b\) and the actual final speed of the Viper, what do you conclude about how its acceleration changed over time?
20 . The speed required for a low-earth orbit is \(7.9\times10^3\ \text{m}/\text{s}\) (see ch. 10). When a rocket is launched into orbit, it goes up a little at first to get above almost all of the atmosphere, but then tips over horizontally to build up to orbital speed. Suppose the horizontal acceleration is limited to \(3g\) to keep from damaging the cargo (or hurting the crew, for a crewed flight). (a) What is the minimum distance the rocket must travel downrange before it reaches orbital speed? How much does it matter whether you take into account the initial eastward velocity due to the rotation of the earth? (b) Rather than a rocket ship, it might be advantageous to use a railgun design, in which the craft would be accelerated to orbital speeds along a railroad track. This has the advantage that it isn't necessary to lift a large mass of fuel, since the energy source is external. Based on your answer to part a, comment on the feasibility of this design for crewed launches from the earth's surface.
21 . Consider the following passage from Alice in Wonderland, in which Alice has been falling for a long time down a rabbit hole:
Down, down, down. Would the fall never come to an end? “I wonder how many miles I've fallen by this time?” she said aloud. “I must be getting somewhere near the center of the earth. Let me see: that would be four thousand miles down, I think” (for, you see, Alice had learned several things of this sort in her lessons in the schoolroom, and though this was not a very good opportunity for showing off her knowledge, as there was no one to listen to her, still it was good practice to say it over)...
Alice doesn't know much physics, but let's try to calculate the amount of time it would take to fall four thousand miles, starting from rest with an acceleration of 10 \(\ \text{m}/\text{s}^2\). This is really only a lower limit; if there really was a hole that deep, the fall would actually take a longer time than the one you calculate, both because there is air friction and because gravity gets weaker as you get deeper (at the center of the earth, \(g\) is zero, because the earth is pulling you equally in every direction at once). (answer check available at lightandmatter.com)
22 . How many cubic inches are there in a cubic foot? The answer is not 12.(answer check available at lightandmatter.com)
23 .   The answer is not 2.
24 . The population density of Los Angeles is about \(4000\ \text{people}/\text{km}^2\). That of San Francisco is about \(6000\ \text{people}/\text{km}^2\). How many times farther away is the average person's nearest neighbor in LA than in San Francisco? The answer is not 1.5. (answer check available at lightandmatter.com)
25 . A hunting dog's nose has about 10 square inches of active surface. How is this possible, since the dog's nose is only about 1 in \(\times\) 1 in \(\times\) 1 in = 1 \(\text{in}^3?\) After all, 10 is greater than 1, so how can it fit?
26 . Estimate the number of blades of grass on a football field.
27 . In a computer memory chip, each bit of information (a 0 or a 1) is stored in a single tiny circuit etched onto the surface of a silicon chip. The circuits cover the surface of the chip like lots in a housing development. A typical chip stores 64 Mb (megabytes) of data, where a byte is 8 bits. Estimate (a) the area of each circuit, and (b) its linear size.
28 . Suppose someone built a gigantic apartment building, measuring 10 km \(\times\) 10 km at the base. Estimate how tall the building would have to be to have space in it for the entire world's population to live.
29 . A hamburger chain advertises that it has sold 10 billion Bongo Burgers. Estimate the total mass of feed required to raise the cows used to make the burgers.
30 . Estimate the volume of a human body, in \(\text{cm}^3\).
31 . (solution in the pdf version of the book) How many \(\text{cm}^2\) is 1 \(\text{mm}^2?\)
32 . (solution in the pdf version of the book) Compare the light-gathering powers of a 3-cm-diameter telescope and a 30-cm telescope.
33 . (solution in the pdf version of the book) One step on the Richter scale corresponds to a factor of 100 in terms of the energy absorbed by something on the surface of the Earth, e.g., a house. For instance, a 9.3-magnitude quake would release 100 times more energy than an 8.3. The energy spreads out from the epicenter as a wave, and for the sake of this problem we'll assume we're dealing with seismic waves that spread out in three dimensions, so that we can visualize them as hemispheres spreading out under the surface of the earth. If a certain 7.6-magnitude earthquake and a certain 5.6-magnitude earthquake produce the same amount of vibration where I live, compare the distances from my house to the two epicenters.
34 . In Europe, a piece of paper of the standard size, called A4, is a little narrower and taller than its American counterpart. The ratio of the height to the width is the square root of 2, and this has some useful properties. For instance, if you cut an A4 sheet from left to right, you get two smaller sheets that have the same proportions. You can even buy sheets of this smaller size, and they're called A5. There is a whole series of sizes related in this way, all with the same proportions. (a) Compare an A5 sheet to an A4 in terms of area and linear size. (b) The series of paper sizes starts from an A0 sheet, which has an area of one square meter. Suppose we had a series of boxes defined in a similar way: the B0 box has a volume of one cubic meter, two B1 boxes fit exactly inside an B0 box, and so on. What would be the dimensions of a B0 box? (answer check available at lightandmatter.com)
c / Albert Einstein, and his moustache, problem 35 .
36 . According to folklore, every time you take a breath, you are inhaling some of the atoms exhaled in Caesar's last words. Is this true? If so, how many?
37 . The Earth's surface is about 70% water. Mars's diameter is about half the Earth's, but it has no surface water. Compare the land areas of the two planets.(answer check available at lightandmatter.com)
38 . (solution in the pdf version of the book) The traditional Martini glass is shaped like a cone with the point at the bottom. Suppose you make a Martini by pouring vermouth into the glass to a depth of 3 cm, and then adding gin to bring the depth to 6 cm. What are the proportions of gin and vermouth?
39 . The central portion of a CD is taken up by the hole and some surrounding clear plastic, and this area is unavailable for storing data. The radius of the central circle is about 35% of the outer radius of the data-storing area. What percentage of the CD's area is therefore lost? (answer check available at lightandmatter.com)
40 . The one-liter cube in the photo has been marked off into smaller cubes, with linear dimensions one tenth those of the big one. What is the volume of each of the small cubes?(solution in the pdf version of the book)
41 . Estimate the number of man-hours required for building the Great Wall of China. (solution in the pdf version of the book)
42 . (a) Using the microscope photo in the figure, estimate the mass of a one cell of the E. coli bacterium, which is one of the most common ones in the human intestine. Note the scale at the lower right corner, which is 1 \(\mu\text{m}\). Each of the tubular objects in the column is one cell. (b) The feces in the human intestine are mostly bacteria (some dead, some alive), of which E. coli is a large and typical component. Estimate the number of bacteria in your intestines, and compare with the number of human cells in your body, which is believed to be roughly on the order of \(10^{13}\). (c) Interpreting your result from part b, what does this tell you about the size of a typical human cell compared to the size of a typical bacterial cell?
43 . The figure shows a practical, simple experiment for determining \(g\) to high precision.  They fall through unequal heights \(\Delta x_1\) and \(\Delta x_2\). A computer records the sounds through a microphone as first one ball and then the other strikes the floor. From this recording, we can accurately determine the quantity \(T\) defined as \(T=\Delta t_2-\Delta t_1\), i.e., the time lag between the first and second impacts.
(a) Find an equation for \(g\) in terms of the measured quantities \(T\), \(\Delta x_1\) and \(\Delta x_2\).(answer check available at lightandmatter.com)
(b) Check the units of your equation.
(c) Check that your equation gives the correct result in the case where \(\Delta x_1\) is very close to zero. However, is this case realistic?
(d) What happens when \(\Delta x_1=\Delta x_2\)? Discuss this both mathematically and physically.
44 . (solution in the pdf version of the book) Estimate the number of jellybeans in figure o on p. 44.
(c) 1998-2013 Benjamin Crowell, licensed under the Creative Commons Attribution-ShareAlike license . Photo credits are given at the end of the Adobe Acrobat version.
Contributors and Attributions
Benjamin Crowell (Fullerton College). Conceptual Physics is copyrighted with a CC-BY-SA license.


14.19: Discussion- Narrowing the Research Topic
This discussion will help you practice narrowing a topic, a skill you will need in the research process.
STEP 1 : Imagine that you have been assigned a research paper on technology. As you know, this topic is far too broad for a successful research paper. It needs to be narrowed so that you can go deep on a specific topic. Ask yourself the question, “What aspects of technology am I interested in?” and make a list of at least five topics .
STEP 2 : Choose one of your listed topics (ideally the one you find most interesting), and perform some preliminary research (Wikipedia, Google search, etc.). List at least three of the ideas that arise from this research. For example, if your initial topic was “technology’s impact on health,” you might find articles linking social media usage to anxiety and depression, articles discussing how 3D printing can create affordable prosthetics, and articles on eye problems caused by excessive screen time.
STEP 3 : Choose one of these areas and narrow your topic again . For example, if you chose the link between social media and anxiety/depression, you might want to research this phenomenon in teenagers, or you might narrow “social media” to more specific platforms like Instagram or Snapchat. Once you think you have a sufficiently narrow and focused idea, write it out in a question format. For example: What is the relationship between depression/anxiety in teenagers and their use of social media platforms like Instagram and Snapchat?
STEP 4 : Explain and discuss your steps in a discussion post, providing information about how you narrowed your topic and including your finalized research question.
STEP 5 : Respond in two separate posts to two classmates (in at least 75 words). Write about how you might take another approach to the same topic. Explicitly address their examples and try to extend, complicate, or redirect their points in a substantive, knowledge-demonstrating way.
Contributors and Attributions
- Discussion: Narrowing the Research Topic. Authored by : Adrienne Kaufmann for Lumen Learning. Provided by : Lumen Learning. License : CC BY: Attribution


15.9: Conclusion
selected template will load here
This action is not available.
The collapse of the Soviet Union brought neither global peace nor stability, and the attacks of September 11, 2001, plunged the United States into interminable conflicts around the world.  And yet the stream of history changes its course. Trends shift, things change, and events turn. New generations bring with them new perspectives, and they share new ideas with new technologies. Our world is not foreordained. It is the product of history, the ever-evolving culmination of a longer and broader story, of a larger history, of a raw, distinctive, American Yawp.


17.7: The Adrenal Glands
By the end of this section, you will be able to:
- Describe the location and structure of the adrenal glands
- Identify the hormones produced by the adrenal cortex and adrenal medulla, and summarize their target cells and effects
The adrenal glands are wedges of glandular and neuroendocrine tissue adhering to the top of the kidneys by a fibrous capsule (Figure \(\PageIndex{1}\)). The adrenal glands have a rich blood supply and experience one of the highest rates of blood flow in the body. They are served by several arteries branching off the aorta, including the suprarenal and renal arteries. Blood flows to each adrenal gland at the adrenal cortex and then drains into the adrenal medulla. Adrenal hormones are released into the circulation via the left and right suprarenal veins.
Interactive Link
View the University of Michigan WebScope to explore the tissue sample in greater detail.
The adrenal gland consists of an outer cortex of glandular tissue and an inner medulla of nervous tissue. The cortex itself is divided into three zones: the zona glomerulosa , the zona fasciculata , and the zona reticularis . Each region secretes its own set of hormones.
The adrenal cortex , as a component of the hypothalamic-pituitary-adrenal (HPA) axis, secretes steroid hormones important for the regulation of the long-term stress response, blood pressure and blood volume, nutrient uptake and storage, fluid and electrolyte balance, and inflammation. The HPA axis involves the stimulation of hormone release of adrenocorticotropic hormone (ACTH) from the pituitary by the hypothalamus. ACTH then stimulates the adrenal cortex to produce the hormone cortisol. This pathway will be discussed in more detail below.
The adrenal medulla is neuroendocrine tissue composed of postganglionic sympathetic nervous system (SNS) neurons. It is really an extension of the autonomic nervous system, which regulates homeostasis in the body. The sympathomedullary (SAM) pathway involves the stimulation of the medulla by impulses from the hypothalamus via neurons from the thoracic spinal cord. The medulla is stimulated to secrete the amine hormones epinephrine and norepinephrine.
One of the major functions of the adrenal gland is to respond to stress. Stress can be either physical or psychological or both. Physical stresses include exposing the body to injury, walking outside in cold and wet conditions without a coat on, or malnutrition. Psychological stresses include the perception of a physical threat, a fight with a loved one, or just a bad day at school.
The body responds in different ways to short-term stress and long-term stress following a pattern known as the general adaptation syndrome (GAS) . Stage one of GAS is called the alarm reaction . This is short-term stress, the fight-or-flight response, mediated by the hormones epinephrine and norepinephrine from the adrenal medulla via the SAM pathway. Their function is to prepare the body for extreme physical exertion. Once this stress is relieved, the body quickly returns to normal. The section on the adrenal medulla covers this response in more detail.
If the stress is not soon relieved, the body adapts to the stress in the second stage called the stage of resistance . If a person is starving for example, the body may send signals to the gastrointestinal tract to maximize the absorption of nutrients from food.
If the stress continues for a longer term however, the body responds with symptoms quite different than the fight-or-flight response. During the stage of exhaustion , individuals may begin to suffer depression, the suppression of their immune response, severe fatigue, or even a fatal heart attack. These symptoms are mediated by the hormones of the adrenal cortex, especially cortisol, released as a result of signals from the HPA axis.
Adrenal hormones also have several non–stress-related functions, including the increase of blood sodium and glucose levels, which will be described in detail below.
Adrenal Cortex
The adrenal cortex consists of multiple layers of lipid-storing cells that occur in three structurally distinct regions. Each of these regions produces different hormones.
Interactive Link
Visit this link to view an animation describing the location and function of the adrenal glands. Which hormone produced by the adrenal glands is responsible for the mobilization of energy stores?
Hormones of the Zona Glomerulosa
The most superficial region of the adrenal cortex is the zona glomerulosa, which produces a group of hormones collectively referred to as mineralocorticoids because of their effect on body minerals, especially sodium and potassium. These hormones are essential for fluid and electrolyte balance.
Aldosterone is the major mineralocorticoid. It is important in the regulation of the concentration of sodium and potassium ions in urine, sweat, and saliva. For example, it is released in response to elevated blood K + , low blood Na + , low blood pressure, or low blood volume. In response, aldosterone increases the excretion of K + and the retention of Na + , which in turn increases blood volume and blood pressure. Its secretion is prompted when CRH from the hypothalamus triggers ACTH release from the anterior pituitary.
Aldosterone is also a key component of the renin-angiotensin-aldosterone system (RAAS) in which specialized cells of the kidneys secrete the enzyme renin in response to low blood volume or low blood pressure. Renin then catalyzes the conversion of the blood protein angiotensinogen, produced by the liver, to the hormone angiotensin I. Angiotensin I is converted in the lungs to angiotensin II by angiotensin-converting enzyme (ACE). Angiotensin II has three major functions:
- Initiating vasoconstriction of the arterioles, decreasing blood flow
- Stimulating kidney tubules to reabsorb NaCl and water, increasing blood volume
- Signaling the adrenal cortex to secrete aldosterone, the effects of which further contribute to fluid retention, restoring blood pressure and blood volume
For individuals with hypertension, or high blood pressure, drugs are available that block the production of angiotensin II. These drugs, known as ACE inhibitors, block the ACE enzyme from converting angiotensin I to angiotensin II, thus mitigating the latter’s ability to increase blood pressure.
Hormones of the Zona Fasciculata
The intermediate region of the adrenal cortex is the zona fasciculata, named as such because the cells form small fascicles (bundles) separated by tiny blood vessels. The cells of the zona fasciculata produce hormones called glucocorticoids because of their role in glucose metabolism. The most important of these is cortisol , some of which the liver converts to cortisone. A glucocorticoid produced in much smaller amounts is corticosterone. In response to long-term stressors, the hypothalamus secretes CRH, which in turn triggers the release of ACTH by the anterior pituitary. ACTH triggers the release of the glucocorticoids. Their overall effect is to inhibit tissue building while stimulating the breakdown of stored nutrients to maintain adequate fuel supplies. In conditions of long-term stress, for example, cortisol promotes the catabolism of glycogen to glucose, the catabolism of stored triglycerides into fatty acids and glycerol, and the catabolism of muscle proteins into amino acids. These raw materials can then be used to synthesize additional glucose and ketones for use as body fuels. The hippocampus, which is part of the temporal lobe of the cerebral cortices and important in memory formation, is highly sensitive to stress levels because of its many glucocorticoid receptors.
You are probably familiar with prescription and over-the-counter medications containing glucocorticoids, such as cortisone injections into inflamed joints, prednisone tablets and steroid-based inhalers used to manage severe asthma, and hydrocortisone creams applied to relieve itchy rashes. These drugs reflect another role of cortisol—the downregulation of the immune system, which inhibits the inflammatory response.
Hormones of the Zona Reticularis
The deepest region of the adrenal cortex is the zona reticularis, which produces small amounts of a class of steroid sex hormones called androgens. During puberty and most of adulthood, androgens are produced in the gonads. The androgens produced in the zona reticularis supplement the gonadal androgens. They are produced in response to ACTH from the anterior pituitary and are converted in the tissues to testosterone or estrogens. In adult females, they may contribute to the sex drive, but their function in adult males is not well understood. In post-menopausal people, as the functions of the ovaries decline, the main source of estrogens becomes the androgens produced by the zona reticularis.
Adrenal Medulla
As noted earlier, the adrenal cortex releases glucocorticoids in response to long-term stress such as severe illness. In contrast, the adrenal medulla releases its hormones in response to acute, short-term stress mediated by the sympathetic nervous system (SNS).
The medullary tissue is composed of unique postganglionic SNS neurons called chromaffin cells, which are large and irregularly shaped, and produce the neurotransmitters epinephrine (also called adrenaline) and norepinephrine (or noradrenaline). Epinephrine is produced in greater quantities—approximately a 4 to 1 ratio with norepinephrine—and is the more powerful hormone. Because the chromaffin cells release epinephrine and norepinephrine into the systemic circulation, where they travel widely and exert effects on distant cells, they are considered hormones. Derived from the amino acid tyrosine, they are chemically classified as catecholamines.
The secretion of medullary epinephrine and norepinephrine is controlled by a neural pathway that originates from the hypothalamus in response to danger or stress (the SAM pathway). Both epinephrine and norepinephrine signal the liver and skeletal muscle cells to convert glycogen into glucose, resulting in increased blood glucose levels. These hormones increase the heart rate, pulse, and blood pressure to prepare the body to fight the perceived threat or flee from it. In addition, the pathway dilates the airways, raising blood oxygen levels. It also prompts vasodilation, further increasing the oxygenation of important organs such as the lungs, brain, heart, and skeletal muscle. At the same time, it triggers vasoconstriction to blood vessels serving less essential organs such as the gastrointestinal tract, kidneys, and skin, and downregulates some components of the immune system. Other effects include a dry mouth, loss of appetite, pupil dilation, and a loss of peripheral vision. The major hormones of the adrenal glands are summarized in Table \(\PageIndex{1}\).
| Adrenal gland | Associated hormones | Chemical class | Effect |
|---|---|---|---|
| Adrenal cortex | Aldosterone | Steroid | Increases blood Na + levels |
| Adrenal cortex | Cortisol, corticosterone, cortisone | Steroid | Increase blood glucose levels |
| Adrenal medulla | Epinephrine, norepinephrine | Amine | Stimulate fight-or-flight response |
Disorders Involving the Adrenal Glands
Several disorders are caused by the dysregulation of the hormones produced by the adrenal glands. For example, Cushing’s disease is a disorder characterized by high blood glucose levels and the accumulation of lipid deposits on the face and neck. It is caused by hypersecretion of cortisol. The most common source of Cushing’s disease is a pituitary tumor that secretes cortisol or ACTH in abnormally high amounts. Other common signs of Cushing’s disease include the development of a moon-shaped face, a buffalo hump on the back of the neck, rapid weight gain, and hair loss. Chronically elevated glucose levels are also associated with an elevated risk of developing type 2 diabetes. In addition to hyperglycemia, chronically elevated glucocorticoids compromise immunity, resistance to infection, and memory, and can result in rapid weight gain and hair loss.
In contrast, the hyposecretion of corticosteroids can result in Addison’s disease, a rare disorder that causes low blood glucose levels and low blood sodium levels. The signs and symptoms of Addison’s disease are vague and are typical of other disorders as well, making diagnosis difficult. They may include general weakness, abdominal pain, weight loss, nausea, vomiting, sweating, and cravings for salty food.


1.1: Exercises
Use an index card or a piece of paper folded lengthwise, and cover up the right-hand column of the exercises below. Read each exercise in the left-hand column, answer it in your mind, then slide the index card down to reveal the answer and see if you’re right! For every exercise you missed, figure out why you missed it before moving on.
| Q | A |
|---|---|
| What’s the opposite of concrete? | Abstract. |
| What’s the opposite of discrete? | Continuous. |
| Consider a quantity of water in a glass. Would you call it abstract, or concrete? Discrete, or continuous? | Concrete, since it’s a real entity you can experience with the senses. Continuous, since it could be any number of ounces (or liters, or tablespoons, or whatever). The amount of water certainly doesn’t have to be an integer. (Food for thought: since all matter is ultimately comprised of atoms, are even substances like water discrete?) |
| Consider the number 27. Would you call it abstract, or concrete? Discrete, or continuous? | Abstract, since you can’t see or touch or smell “twenty-seven." Probably discrete, since it’s an integer, and when we think of whole numbers we think “discrete." (Food for thought: in real life, how would you know whether I meant the integer “27" or the decimal number “27.0?" And does it matter?) |
| Consider a bit in a computer’s memory. Would you call it abstract, or concrete? Discrete, or continuous? | Clearly it’s discrete. Abstract vs. concrete, though, is a little tricky. If we’re talking about the actual transistor and capacitor that’s physically present in the hardware, holding a tiny charge in some little chip, then it’s concrete. But if we’re talking about the value “1" that is conceptually part of the computer’s currently executing state, then it’s really abstract just like 27 was. In this book, we’ll always be talking about bits in this second, abstract sense. |
| If math isn’t just about numbers, what else is it about? | Any kind of abstract object that has properties we can reason about. |


10.10: Personality Theory in Real Life
-
- Last updated
- Save as PDF
Reconceptualizing Personality Disorders within the Context of the Five-Factor Model
There remains debate as to exactly how personality disorders should be classified (see the Appendix). This issue is more than just a matter of curiosity, since our entire conception of personality disorders is an essential factor in how we approach their treatment. As perhaps the most widely accepted and scientifically validated trait perspective on normal personality, it stands to reason that the Five-Factor Model (FFM) ought to also provide a basis for classifying abnormal personality and, in particular, the personality disorders. Thus, Costa and Widiger (1994) brought together a group of experts, including Theodore Millon, to address personality disorders within the context of the FFM.
The DSM-III and DSM-IV use diagnostic categories for the personality disorders, whereas the FFM suggests a dimensional approach. The categorical approach has several advantages. It is relatively easier to conceptualize disorders as either having them or not, clinicians are familiar with the current categories, and when clinical decisions are categorical they tend to be consistent. However, the dimensional approach offers the advantages of not being arbitrary in defining specific symptom cut-off points for a diagnosis, they allow for retaining information on those patients who just miss the cut-off point for a diagnosis (and could, therefore, simply be classified as not having the disorder), and the dimensions are more flexible than a categorical diagnosis. More importantly than just speculating on advantages and disadvantages, however, is that the majority of empirical data seems to support the dimensional approach (Widiger & Frances, 1994). For example, borderline personality disorder patients do not show a specific profile on the MMPI, but rather a nonspecific elevation across most scales. Diagnosis is typically made following a clinical evaluation including an interview. A similar challenge faces clinicians using the NEO-PI (the assessment tool specifically designed for the FFM), but useful and relevant data are available from looking at the specific trait scores within factors, particularly within the factor neuroticism (Trull & McCrae, 1994). In addition, factor analysis on the dimensions of personality disorder yielded results that fit very well with the FFM, with several aspects of personality disorder (but not all) again being linked to neuroticism (Schroeder, Wormworth, & Livesley, 1994). It is important to remember, however, that the very idea of using a dimensional approach is based, in part, on an assumption:
…If one assumes that disordered personality is qualitatively different from normal personality, then the inclusion of a dimensional model of personality may be insufficient or inappropriate for investigation. If one assumes that disordered personality reflects quantitative differences in the manifestation or severity of normal personality traits (i.e., a dimensional approach), then the adoption of a personality taxonomy for use as a structural referent becomes a necessary or even fundamental conceptual task. (pp. 73-74; Wiggins & Pincus, 1994)
What, then, might personality disorders look like in terms of a dimensional description? Clark, Vorhies, and McEwen (1994) take an integrated approach based on two basic propositions pertaining to traits: first, that they are continuously distributed and exhibit wide individual variation; and second, that they are not fixed, but rather they are adaptations to the environment that are consistent within one’s individual range. These two points lead to the notions that a single trait structure can represent both normal and abnormal personality, that within the normal range there is great individual difference in each person’s characteristic and adaptive styles of thinking, feeling, and behaving, and that personality disorders are characterized by extreme and inflexible expressions of the normal personality structure. When examining data from individuals diagnosed with personality disorder, they have identified symptom clusters that form dimensions, or factors, which once again fit well with the FFM (Clark, et al., 1994). Widiger and several colleagues have actually offered five-factor translations of the standard categories of DSM-III and DSM-IV personality disorders (see Widiger, et al., 1994). The purpose of these translations is to take the personality disorder categories that psychologists are familiar with and put them in terms of the FFM. Consider two examples:
Paranoid Personality Disorder: Paranoid personality disorder (PAR) involves interpreting the actions of others as threatening or deliberately demeaning. These individuals tend to be suspicious, mistrustful, hypervigilant, and argumentative. According to the FFM, PAR is characterized primarily by excessively low agreeableness, particularly on the suspiciousness facet (a facet is one of the traits that makes up a factor). They are also characterized by the low agreeableness facets of very low straightforwardness and compliance, which represent the PAR tendencies to be secretive and oppositional. PAR is also characterized by the angry hostility facet of neuroticism, low extraversion, and low openness.
Antisocial Personality Disorder: Antisocial personality disorder (ATS) is characterized by irresponsible and antisocial behavior, and often involves criminal activity and a lack of regard for the rights of others. Within the FFM, they score excessively low on conscientiousness and agreeableness (particularly low on the facets of straightforwardness, altruism, compliance, and tendermindedness). They score high on the neuroticism facets of hostility, anxiety, depression, and impulsivity. However, so-called “successful” psychopaths may be characterized by very low levels of anxiety and self-consciousness.
(see Widiger, et al., 1994)
So, given the possibility of reconceptualizing personality disorders within the FFM, is it something we should do? Millon suggests that we view personality as the psychological equivalent of the body’s biological systems. Personality is, in this conception, a psychic system of structures and functions that lead to characteristic patterns of thought, feeling, and behavior. These characteristics cannot be viewed as simply normal or abnormal, since any specific element of the personality might be adaptive in one situation but maladaptive in another. Thus, the dimensional approach to describing personality provides a comprehensive picture in which little information of potential significance is lost (Millon, 1994). McCrae questions the very validity of Axis II of the DSM system, which appears to have little empirical support. He suggests that clinicians include in their diagnosis of patients a global assessment of the five personality factors. Thus, the diagnostic report would provide the necessary information on personality pertaining to the common symptoms and problems associated with either high or low scores on each factor (McCrae, 1994; Widiger, 1994). For example:
High Neuroticism: chronic negative affects, difficulty in inhibiting impulses, irrational beliefs
Low Neuroticism: lack of appropriate concern for potential problems in health or social adjustment, emotional blandness
High Agreeableness: gullibility, excessive candor and generosity, inability to stand up to others, easily taken advantage of
Low Agreeableness: cynicism and paranoid thinking, inability to trust, quarrelsomeness, too ready to pick fights, exploitative and manipulative, lying, rude and inconsiderate
(see McCrae, 1994)
Perhaps the most valuable aspect of any model used for classifying the personality disorders is its ability to provide guidelines for conceptualizing a treatment strategy. Sanderson and Clarkin (1994) have indeed found the NEO-PI useful in differential treatment planning. For example, the NEO-PI, in conjunction with a clinical interview, helps describe the typical interpersonal patterns of the patient, suggesting areas of difficulty needing treatment regardless of whether the therapy format is individual, family, or a group setting. In addition, the NEO-PI can help to identify which therapy format might be best suited to each particular patient. Although Sanderson and Clarkin (1994) caution that such conceptions still await empirical confirmation, they do offer some examples from their own supportive clinical experience. Likewise, MacKenzie (1994) offers numerous specific examples from cases in which factor scores provided clear target areas for focusing therapy. For example, a women who scored high in agreeableness acknowledged that she repeatedly got into relationships in which she felt used, a teacher who scored very high on openness was overly stimulated in new situations and felt overwhelmed with creative ideas, and a man who scored low on conscientiousness felt stuck in life, having worked only itinerant construction jobs despite having earned a graduate degree in college. In each case, the NEO-PI data matched the clinical presentation quite well, suggesting that the FFM would indeed be an effective conceptualization of treatment strategies for personality disorder issues (as well as, presumably, for other psychological and adjustment disorders).
The diagnosis of personality disorders, whether categorical or dimensional, remains a controversial topic. Of even greater concern, is the resistance of these disorders to treatment. However, the FFM appears to offer an advantageous way of describing personality disorder as an extreme extension of normal personality dimensions, and the NEO-PI scales offer practical direction with regard to treatment strategies. Change, however, may not come easily:
Some observers have said that what is at issue here is the American Psychiatric Association “versus” the American Psychological Association. In other words, the potential conflict between psychiatric/categorical and psychological/dimensional models could stall progress in this field. It has been suggested that the American Psychological Association should issue a rival DSM that uses a dimensional approach. We believe a far better solution would be cooperation between the two approaches, which would lead to more coordinated research and shared clinical experience. (pg. 325; Costa & Widiger, 1994).


9: Rhetorical Analysis- Interpreting the Art of Rhetoric
Figure \(9.1\) To be effective, persuasive speeches depend on rhetoric. In this photograph, suffragist Elsie Hill (1883–1970) speaks forcefully to a street gathering in St. Paul, Minnesota, in July 1916. When advocating for women’s suffrage, Hill, like other orators, relied on rhetorical strategies to persuade audiences that might have disagreed with her platform. Conversely, some audience members could recognize her strategies and know how she was using language to persuade them. Those people, consciously or not, were engaged in rhetorical analysis. (credit: “Elsie Hill speaking [at street meeting in St. Paul, Minn., during Prohibition Party convention that endorsed a plank advocating a suffrage amendment, July 1916]” by Harris & Ewing, Washington, D.C./Wikimedia Commons/ Library of Congress, Public Domain)
Chapter Outline
Introduction
Because humans exist in social situations, communication has always been a part of what it means to be human. Basic forms of communication, such as smiling or adopting certain physical stances, may be considered instinctive. However, when language began to replace sounds and gestures, communication became more specific. People used language to give and seek information, to express and react to emotions, and to persuade others to think or act in certain ways.
Beginning with the ancient Greeks, a large part of language education has focused on the ability to persuade. The Greeks used the word rhetoric , which originally meant “the act of speaking a language,” and expanded its importance to include a focus on situations in which language was used for a persuasive purpose: to motivate an audience to action.
These ideas became central to Greek culture and patterns of behavior that characterized their way of life. This chapter will address persuasive techniques: how people use words to influence, lead, create new understanding, and rouse others to action. Your writing task will be to identify, explain, and analyze the strategies a particular writer uses to persuade readers. Analyzing the rhetorical strategies of other writers will help you develop your writing identity as you learn to incorporate some of these strategies into your own work while rejecting others.


7.3: Frazier v. Cupp 394 US 731 (1969)
U.S. Supreme Court
Frazier v. Cupp, 394 U.S. 731 (1969)
Frazier v. Cupp
No. 643
Argued February 26, 1969
Decided April 22, 1969
394 U.S. 731
CERTIORARI TO THE UNITED STATES COURT OF APPEALS
FOR THE NINTH CIRCUIT
Petitioner in this habeas corpus proceeding claims that his constitutional rights were violated in three respects in his trial in 1965 for murder for which he had been indicted jointly with one Rawls, who pleaded guilty. (1) The prosecutor, on the basis of previous information he had received that Rawls would testify, included in his opening statement a brief summary of Rawls’ expected testimony. When Rawls was called to the stand, he claimed his privilege against self-incrimination, and was dismissed. Petitioner’s motions for a mistrial were overruled. The trial court instructed the jury that the opening statements of counsel should not be considered as evidence. (2) After preliminary questioning shortly after his arrest, petitioner was told that he could have an attorney if he wanted one and that anything he said could be used against him at trial. Thereafter the interrogating officer falsely told petitioner, who was reluctant to talk, that Rawls had confessed. Petitioner later began to spill his story, but again showed signs of reluctance and said he thought he better get a lawyer before he talked any more. Following the officer’s reply that petitioner could not be in any more trouble than he was in, petitioner fully confessed and, after further warnings, signed a written confession, which was later admitted into evidence over petitioner’s objection. (3) Also admitted into evidence was some clothing which officers had seized from petitioner’s duffel hag which he and Rawls had used jointly and which the officers had found during a search conducted with Rawls’ consent. Petitioner was convicted, and the State Supreme Court affirmed. Petitioner thereafter filed a petition for a writ of habeas corpus in the District Court, which granted the writ. The Court of Appeals reversed. Petitioner claims that the prosecutor’s use of the summarized Rawls statement denied him his constitutional rights of confrontation as guaranteed by the Sixth and Fourteenth Amendments; that his confession contravened the principles established by Escobedo v. Illinois, 378 U. S. 478 (1964), and Miranda v. Arizona, 384 U. S. 436 (1966), and was involuntary, and that the clothing had been illegally seized in violation of the Fourth and Fourteenth Amendments.
Held: 1. On the facts here, where the evidence which the prosecutor reasonably expected to produce was objectively and briefly summarized and was not touted to the jury as crucial to the prosecution’s case, the court’s limiting instructions were sufficient to protect petitioner’s constitutional rights. Douglas v. Alabama, 380 U. S. 415 (1965), and Bruton v. United States, 391 U. S. 123 (1968), distinguished. Pp. 394 U. S. 734 -737.
2. In the context of this case, where it is possible that the questioning officer took petitioner’s remark about seeing an attorney not as a request that the interrogation cease but as a passing comment, there was no denial of the right to counsel such as existed in Escobedo, and Miranda, which was decided after petitioner’s trial, is inapplicable under Johnson v. New Jersey, 384 U. S. 719 (1966). Pp. 394 U. S. 738 -739.
3. On the facts of this case and in view of the “totality of the circumstances,” the trial court did not err in holding that petitioner’s confession was voluntary. P. 394 U. S. 739 .
4. The clothing from petitioner’s duffel bag was found in the course of a lawful search since Rawls, a joint user of the bag, had authority to consent to its search. P. 394 U. S. 740 .
388 F.2d 777, affirmed.
MR. JUSTICE MARSHALL delivered the opinion of the Court.
Petitioner was convicted in an Oregon state court of second-degree murder in connection with the September 22, 1964, slaying of one Russell Anton Marleau. After the Supreme Court of Oregon had affirmed his conviction, 245 Ore. 4, 418 P.2d 841 (1966), petitioner filed a petition for a writ of habeas corpus in the United States District Court for the District of Oregon. The District Court granted the writ, but the Court of Appeals for the Ninth Circuit reversed, 388 F.2d 777 (1968). We
Home Page 394 U. S. 733
granted certiorari to consider three contentions of error raised by petitioner. 393 U. S. 821 (1968). Although petitioner’s case has been ably briefed and argued by appointed counsel, we find none of these allegations sufficient to warrant reversal.
I
Petitioner’s first argument centers on certain allegedly prejudicial remarks made during the prosecutor’s opening statement. Petitioner had been indicted jointly with his cousin, Jerry Lee Rawls, who pleaded guilty to the same offense. Prior to petitioner’s trial, petitioner’s defense counsel told the prosecutor that Rawls would invoke his privilege against self-incrimination if he were called to the stand; defense counsel warned the prosecutor not to rely in his opening statement upon Rawls’ expected testimony. The prosecutor replied that he would act on the basis of “all of the information I have concerning [Rawls’] testimony.” Before trial, he consulted with a police officer who had spoken to Rawls and with Rawls’ probation officer; each indicated his belief that Rawls would testify. Similar information came, through a sheriff’s report, from some of Rawls’ close relatives. Because of these reports, the prosecutor concluded that Rawls would testify if asked to do so. The court below felt that the prosecutor also relied on the fact that Rawls had pleaded guilty and was awaiting sentence. This would give him reason, the court felt, to cooperate with the prosecutor.
In any case, after the trial began, the prosecutor included in his opening statement a summary of the testimony he expected to receive from Rawls. The summary was not emphasized in any particular way; it took only a few minutes to recite, and was sandwiched between a summary of petitioner’s own confession and a description of the circumstantial evidence the State would introduce.
At one point, the prosecutor referred to a paper he was holding in his hands to refresh his memory about something Rawls had said. Although the State admitted in argument here that the jury might fairly have believed that the prosecutor was referring to Rawls’ statement, he did not explicitly tell the jury that this paper was Rawls’ confession, nor did he purport to read directly from it. A motion for a mistrial was made at the close of the opening statement, but it was denied. Later, the prosecutor called Rawls to the stand. Rawls informed the court that he intended to assert his privilege against self-incrimination in regard to every question concerning his activities on the morning of September 22, 1964. The matter was not further pursued, and Rawls was dismissed from the stand. His appearance could not have lasted more than two or three minutes. The motion for mistrial was renewed and once again denied.
Petitioner argues that this series of events placed the substance of Rawls’ statement before the jury in a way that “may well have been the equivalent in the jury’s mind of testimony,” Douglas v. Alabama, 380 U. S. 415 , 380 U. S. 419 (1965), and that, as in Bruton v. United States, 391 U. S. 123 , 391 U. S. 128 (1968), the statement “added substantial, perhaps even critical, weight to the Government’s case in a form not subject to cross-examination. . . .” In this way, petitioner claims he was denied his constitutional right of confrontation, guaranteed by the Sixth and Fourteenth Amendments to the Constitution. See Pointer v. Texas, 380 U. S. 400 (1965). Although the judge did caution the jurors that they “must not regard any statement made by counsel in your presence during the proceedings concerning the facts of this case as evidence,” petitioner contends that Bruton v. United States, supra, disposes of the contention that limiting instructions of this sort can be relied upon to cure the error which occurred. Although the question thus posed is not an easy one, we cannot agree with petitioner’s conclusion. First of all, it is clear that this case is quite different from either Douglas or Bruton. In Douglas, the prosecutor called the defendant’s coconspirator to the stand and read his alleged confession to him; the coconspirator was required to assert his privilege against self-incrimination repeatedly as the prosecutor asked him to confirm or deny each statement. The Court found that this procedure placed powerfully incriminating evidence before the jury in a manner which effectively denied the right of cross-examination. Here, Rawls was on the stand for a very short time and only a paraphrase of the statement was placed before the jury. This was done not during the trial, while the person making the statement was on the stand, but in an opening statement. In addition, the jury was told that the opening statement should not be considered as evidence. Certainly the impact of the procedure used here was much less damaging than was the case in Douglas. And unlike the situation in Bruton, the jury was not being asked to perform the mental gymnastics of considering an incriminating statement against only one of two defendants in a joint trial. Moreover, unlike the situation in either Douglas or Bruton, Rawls’ statement was not a vitally important part of the prosecution’s case.
We believe that, in these circumstances the limiting instructions given were sufficient to protect petitioner’s constitutional rights. * As the Court said in Bruton, 391 U.S. at 391 U. S. 135 ,
“Not every admission of inadmissible hearsay or other evidence can be considered to be reversible error unavoidable through limiting instructions; instances occur in almost every trial where inadmissible evidence creeps in, usually inadvertently.”
See Hopt v. Utah, 120
U.S. 430, 120 U. S. 438 (1887). It may be that some remarks included in an opening or closing statement could be so prejudicial that a finding of error, or even constitutional error, would be unavoidable. But here we have no more than an objective summary of evidence which the prosecutor reasonably expected to produce. Many things might happen during the course of the trial which would prevent the presentation of all the evidence described in advance. Certainly not every variance between the advance description and the actual presentation constitutes reversible error, when a proper limiting instruction has been given. Even if it is unreasonable to assume that a jury can disregard a coconspirator’s statement when introduced against one of two joint defendants, it does not seem at all remarkable to assume that the jury will ordinarily be able to limit its consideration to the evidence introduced during the trial. At least where the anticipated, and unproduced, evidence is not touted to the jury as a crucial part of the prosecution’s case,
“it is hard for us to imagine that the minds of the jurors would be so influenced by such incidental statements during this long trial that they would not appraise the evidence objectively and dispassionately.”
United States v. Socony-Vacuum Oil Co., 310 U. S. 150 , 310 U. S. 239 (1940).
The Court of Appeals seemed to feel that this aspect of the case turned on whether or not the prosecutor acted “in a good faith expectation that Rawls would testify.” 388 F.2d at 780-781. While we do not believe that the prosecutor’s good faith, or lack of it, is controlling in determining whether a defendant has been deprived of the right of confrontation guaranteed by the Sixth and Fourteenth Amendments, we agree with the Court of Appeals’ factual determination in this case. The evidence presented in the record is sufficient to support the Oregon Supreme Court’s conclusion that “the state could reasonably expect [Rawls] to testify in line with his previous statements.” 245 Ore. at 9, 418 P.2d at 843. Accordingly, there is no need to decide whether the type of prosecutorial misconduct alleged to have occurred would have been sufficient to constitute reversible constitutional error. Cf. Miller v. Pate, 386 U. S. 1 (1967). Therefore, because we find neither prosecutorial misconduct nor a deprivation of the right of confrontation, we agree with the Court of Appeals that nothing which occurred during the prosecution’s opening statement would warrant federal habeas relief.
II
Petitioner’s second argument concerns the admission into evidence of his own confession. The circumstances under which the confession was obtained can be summarized briefly. Petitioner was arrested about 4:15 p.m. on September 24, 1964. He was taken to headquarters, where questioning began at about 5 p.m. The interrogation, which was tape-recorded, ended slightly more than an hour later, and by 6:45 p.m. petitioner had signed a written version of his confession.
After the questioning had begun and after a few routine facts were ascertained, petitioner was questioned briefly about the location of his Marine uniform. He was not asked where he was on the night in question. Although he admitted that he was with his cousin Rawls, he denied being with any third person. Then petitioner was given a somewhat abbreviated description of his constitutional rights. He was told that he could have an attorney if he wanted one and that anything he said could be used against him at trial. Questioning thereafter became somewhat more vigorous, but petitioner continued to deny being with anyone but Rawls. At this point, the officer questioning petitioner told him, falsely, that Rawls had been brought in and that he had confessed. Petitioner still was reluctant to talk, but after the officer sympathetically suggested that the victim had started a fight by making homosexual advances, petitioner began to spill out his story. Shortly after he began, he again showed signs of reluctance, and said, “I think I had better get a lawyer before I talk any more. I am going to get into trouble more than I am in now.” The officer replied simply, “You can’t be in any more trouble than you are in now,” and the questioning session proceeded. A full confession was obtained and, after further warnings, a written version was signed.
Since petitioner was tried after this Court’s decision in Escobedo v. Illinois, 378 U. S. 478 (1964), but before the decision in Miranda v. Arizona, 384 U. S. 436 (1966), only the rule of the former case is directly applicable. Johnson v. New Jersey, 384 U. S. 719 (1966). Petitioner argues that his statement about getting a lawyer was sufficient to bring Escobedo into play, and that the police should immediately have stopped the questioning and obtained counsel for him. We might agree were Miranda applicable to this case, for, in Miranda, this Court held that,
“[i]f . . . [a suspect] indicates in any manner and at any stage of the process that he wishes to consult with an attorney before speaking, there can be no questioning.”
384 U.S. at 384 U. S. 444 -445. But Miranda does not apply to this case. This Court, in Johnson v. New Jersey, pointedly rejected the contention that the specific commands of Miranda should apply to all post- Escobedo cases. The Court recognized “[t]he disagreements among other courts concerning the implications of Escobedo, ” Johnson v. New Jersey, supra, at 384 U. S. 734 , and concluded that the States, although free to apply Miranda to post- Escobedo cases, id. at 384 U. S. 733 , were not required to do so. The Oregon Supreme Court, in affirming petitioner’s conviction, concluded that the confession was properly introduced into evidence. Under Johnson, we would be free to disagree with this conclusion only if we felt compelled to do so by the specific holding of Escobedo.
We do not believe that Escobedo covers this case. Petitioner’s statement about seeing an attorney was neither as clear nor as unambiguous as the request Escobedo made. The police in Escobedo were unmistakably informed of their suspect’s wishes; in fact, Escobedo’s attorney was present and repeatedly requested permission to see his client. Here, on the other hand, it is possible that the questioning officer took petitioner’s remark not as a request that the interrogation cease, but merely as a passing comment. Petitioner did not pursue the matter, but continued answering questions. In this context, we cannot find the denial of the right to counsel which was found so crucial in Escobedo.
Petitioner also presses the alternative argument that his confession was involuntary, and that it should have been excluded for that reason. The trial judge, after an evidentiary hearing during which the tape recording was played, could not agree with this contention, and our reading of the record does not lead us to a contrary conclusion. Before petitioner made any incriminating statements, he received partial warnings of his constitutional rights; this is, of course, a circumstance quite relevant to a finding of voluntariness. Davis v. North Carolina, 384 U. S. 737 , 384 U. S. 740 -741 (1966). The questioning was of short duration, and petitioner was a mature individual of normal intelligence. The fact that the police misrepresented the statements that Rawls had made is, while relevant, insufficient, in our view, to make this otherwise voluntary confession inadmissible. These cases must be decided by viewing the “totality of the circumstances,” see, e.g., Clewis v. Texas, 386 U. S. 707 , 386 U. S. 708 (1967), and, on the facts of this case, we can find no error in the admission of petitioner’s confession.
III
Petitioner’s final contention can be dismissed rather quickly. He argues that the trial judge erred in permitting some clothing seized from petitioner’s duffel bag to be introduced into evidence. This duffel bag was being used jointly by petitioner and his cousin Rawls, and it had been left in Rawls’ home. The police, while arresting Rawls, asked him if they could have his clothing. They were directed to the duffel bag, and both Rawls and his mother consented to its search. During this search, the officers came upon petitioner’s clothing, and it was seized as well. Since Rawls was a joint user of the bag, he clearly had authority to consent to its search. The officers therefore found evidence against petitioner while in the course of an otherwise lawful search. Under this Court’s past decisions, they were clearly permitted to seize it. Harris v. United States, 390 U. S. 234 (1968); Warden v. Hayden, 387 U. S. 294 (1967). Petitioner argues that Rawls only had actual permission to use one compartment of the bag, and that he had no authority to consent to a search of the other compartments. We will not, however, engage in such metaphysical subtleties in judging the efficacy of Rawls’ consent. Petitioner, in allowing Rawls to use the bag and in leaving it in his house, must be taken to have assumed the risk that Rawls would allow someone else to look inside. We find no valid search and seizure claim in this case.
Because we find none of petitioner’s contentions meritorious, we affirm the judgment of the Court of Appeals.
Affirmed.
MR. CHIEF JUSTICE WARREN and MR. JUSTICE DOUGLAS concur in the result.
MR. JUSTICE FORTAS took no part in the consideration or decision of this case.
* A more specific limiting instruction might have been desirable, but none was requested.
Contributors and Attributions
- Authored by : US Government . Located at : https://supreme.justia.com/cases/federal/us/394/731/case.html . License : Public Domain: No Known Copyright


1.1: Book I
THE GODS IN COUNCIL—MINERVA’S VISIT TO ITHACA—THE CHALLENGE FROM TELEMACHUS TO THE SUITORS.
Tell me, O Muse, of that ingenious hero who travelled far and wide after he had sacked the famous town of Troy. Many cities did he visit, and many were the nations with whose manners and customs he was acquainted; moreover he suffered much by sea while trying to save his own life and bring his men safely home; but do what he might he could not save his men, for they perished through their own sheer folly in eating the cattle of the Sun-god Hyperion; so the god prevented them from ever reaching home. Tell me, too, about all these things, oh daughter of Jove, from whatsoever source you may know them.
So now all who escaped death in battle or by shipwreck had got safely home except Ulysses, and he, though he was longing to return to his wife and country, was detained by the goddess Calypso, who had got him into a large cave and wanted to marry him. But as years went by, there came a time when the gods settled that he should go back to Ithaca; even then, however, when he was among his own people, his troubles were not yet over; nevertheless all the gods had now begun to pity him except Neptune, who still persecuted him without ceasing and would not let him get home.
Now Neptune had gone off to the Ethiopians, who are at the world’s end, and lie in two halves, the one looking West and the other East. 1 He had gone there to accept a hecatomb of sheep and oxen, and was enjoying himself at his festival; but the other gods met in the house of Olympian Jove, and the sire of gods and men spoke first. At that moment he was thinking of Aegisthus, who had been killed by Agamemnon’s son Orestes; so he said to the other gods:
“See now, how men lay blame upon us gods for what is after all nothing but their own folly. Look at Aegisthus; he must needs make love to Agamemnon’s wife unrighteously and then kill Agamemnon, though he knew it would be the death of him; for I sent Mercury to warn him not to do either of these things, inasmuch as Orestes would be sure to take his revenge when he grew up and wanted to return home. Mercury told him this in all good will but he would not listen, and now he has paid for everything in full.”
Then Minerva said, “Father, son of Saturn, King of kings, it served Aegisthus right, and so it would any one else who does as he did; but Aegisthus is neither here nor there; it is for Ulysses that my heart bleeds, when I think of his sufferings in that lonely sea-girt island, far away, poor man, from all his friends. It is an island covered with forest, in the very middle of the sea, and a goddess lives there, daughter of the magician Atlas, who looks after the bottom of the ocean, and carries the great columns that keep heaven and earth asunder. This daughter of Atlas has got hold of poor unhappy Ulysses, and keeps trying by every kind of blandishment to make him forget his home, so that he is tired of life, and thinks of nothing but how he may once more see the smoke of his own chimneys. You, sir, take no heed of this, and yet when Ulysses was before Troy did he not propitiate you with many a burnt sacrifice? Why then should you keep on being so angry with him?”
And Jove said, “My child, what are you talking about? How can I forget Ulysses than whom there is no more capable man on earth, nor more liberal in his offerings to the immortal gods that live in heaven? Bear in mind, however, that Neptune is still furious with Ulysses for having blinded an eye of Polyphemus king of the Cyclopes. Polyphemus is son to Neptune by the nymph Thoosa, daughter to the sea-king Phorcys; therefore though he will not kill Ulysses outright, he torments him by preventing him from getting home. Still, let us lay our heads together and see how we can help him to return; Neptune will then be pacified, for if we are all of a mind he can hardly stand out against us.”
And Minerva said, “Father, son of Saturn, King of kings, if, then, the gods now mean that Ulysses should get home, we should first send Mercury to the Ogygian island to tell Calypso that we have made up our minds and that he is to return. In the meantime I will go to Ithaca, to put heart into Ulysses’ son Telemachus; I will embolden him to call the Achaeans in assembly, and speak out to the suitors of his mother Penelope, who persist in eating up any number of his sheep and oxen; I will also conduct him to Sparta and to Pylos, to see if he can hear anything about the return of his dear father—for this will make people speak well of him.”
So saying she bound on her glittering golden sandals, imperishable, with which she can fly like the wind over land or sea; she grasped the redoubtable bronze-shod spear, so stout and sturdy and strong, wherewith she quells the ranks of heroes who have displeased her, and down she darted from the topmost summits of Olympus, whereon forthwith she was in Ithaca, at the gateway of Ulysses’ house, disguised as a visitor, Mentes, chief of the Taphians, and she held a bronze spear in her hand. There she found the lordly suitors seated on hides of the oxen which they had killed and eaten, and playing draughts in front of the house. Men-servants and pages were bustling about to wait upon them, some mixing wine with water in the mixing-bowls, some cleaning down the tables with wet sponges and laying them out again, and some cutting up great quantities of meat.
Telemachus saw her long before any one else did. He was sitting moodily among the suitors thinking about his brave father, and how he would send them flying out of the house, if he were to come to his own again and be honoured as in days gone by. Thus brooding as he sat among them, he caught sight of Minerva and went straight to the gate, for he was vexed that a stranger should be kept waiting for admittance. He took her right hand in his own, and bade her give him her spear. “Welcome,” said he, “to our house, and when you have partaken of food you shall tell us what you have come for.”
He led the way as he spoke, and Minerva followed him. When they were within he took her spear and set it in the spear-stand against a strong bearing-post along with the many other spears of his unhappy father, and he conducted her to a richly decorated seat under which he threw a cloth of damask. There was a footstool also for her feet, 2 and he set another seat near her for himself, away from the suitors, that she might not be annoyed while eating by their noise and insolence, and that he might ask her more freely about his father.
A maid servant then brought them water in a beautiful golden ewer and poured it into a silver basin for them to wash their hands, and she drew a clean table beside them. An upper servant brought them bread, and offered them many good things of what there was in the house, the carver fetched them plates of all manner of meats and set cups of gold by their side, and a manservant brought them wine and poured it out for them.
Then the suitors came in and took their places on the benches and seats. 3 Forthwith men servants poured water over their hands, maids went round with the bread-baskets, pages filled the mixing-bowls with wine and water, and they laid their hands upon the good things that were before them. As soon as they had had enough to eat and drink they wanted music and dancing, which are the crowning embellishments of a banquet, so a servant brought a lyre to Phemius, whom they compelled perforce to sing to them. As soon as he touched his lyre and began to sing Telemachus spoke low to Minerva, with his head close to hers that no man might hear.
“I hope, sir,” said he, “that you will not be offended with what I am going to say. Singing comes cheap to those who do not pay for it, and all this is done at the cost of one whose bones lie rotting in some wilderness or grinding to powder in the surf. If these men were to see my father come back to Ithaca they would pray for longer legs rather than a longer purse, for money would not serve them; but he, alas, has fallen on an ill fate, and even when people do sometimes say that he is coming, we no longer heed them; we shall never see him again.  Tell me of your town and parents, what manner of ship you came in, how your crew brought you to Ithaca, and of what nation they declared themselves to be—for you cannot have come by land. Tell me also truly, for I want to know, are you a stranger to this house, or have you been here in my father’s time? In the old days we had many visitors for my father went about much himself.”
And Minerva answered, “I will tell you truly and particularly all about it. I am Mentes, son of Anchialus, and I am King of the Taphians. I have come here with my ship and crew, on a voyage to men of a foreign tongue being bound for Temesa 4 with a cargo of iron, and I shall bring back copper. As for my ship, it lies over yonder off the open country away from the town, in the harbour Rheithron 5 under the wooded mountain Neritum. 6 Our fathers were friends before us, as old Laertes will tell you, if you will go and ask him. They say, however, that he never comes to town now, and lives by himself in the country, faring hardly, with an old woman to look after him and get his dinner for him, when he comes in tired from pottering about his vineyard. They told me your father was at home again, and that was why I came, but it seems the gods are still keeping him back, for he is not dead yet not on the mainland. It is more likely he is on some sea-girt island in mid ocean, or a prisoner among savages who are detaining him against his will. I am no prophet, and know very little about omens, but I speak as it is borne in upon me from heaven, and assure you that he will not be away much longer; for he is a man of such resource that even though he were in chains of iron he would find some means of getting home again. But tell me, and tell me true, can Ulysses really have such a fine looking fellow for a son? You are indeed wonderfully like him about the head and eyes, for we were close friends before he set sail for Troy where the flower of all the Argives went also. Since that time we have never either of us seen the other.”
“My mother,” answered Telemachus, “tells me I am son to Ulysses, but it is a wise child that knows his own father. Would that I were son to one who had grown old upon his own estates, for, since you ask me, there is no more ill-starred man under heaven than he who they tell me is my father.”
And Minerva said, “There is no fear of your race dying out yet, while Penelope has such a fine son as you are. But tell me, and tell me true, what is the meaning of all this feasting, and who are these people? What is it all about? Have you some banquet, or is there a wedding in the family—for no one seems to be bringing any provisions of his own? And the guests—how atrociously they are behaving; what riot they make over the whole house; it is enough to disgust any respectable person who comes near them.”
“Sir,” said Telemachus, “as regards your question, so long as my father was here it was well with us and with the house, but the gods in their displeasure have willed it otherwise, and have hidden him away more closely than mortal man was ever yet hidden. I could have borne it better even though he were dead, if he had fallen with his men before Troy, or had died with friends around him when the days of his fighting were done; for then the Achaeans would have built a mound over his ashes, and I should myself have been heir to his renown; but now the storm-winds have spirited him away we know not whither; he is gone without leaving so much as a trace behind him, and I inherit nothing but dismay. Nor does the matter end simply with grief for the loss of my father; heaven has laid sorrows upon me of yet another kind; for the chiefs from all our islands, Dulichium, Same, and the woodland island of Zacynthus, as also all the principal men of Ithaca itself, are eating up my house under the pretext of paying their court to my mother, who will neither point blank say that she will not marry, 7 nor yet bring matters to an end; so they are making havoc of my estate, and before long will do so also with myself.”
“Is that so?” exclaimed Minerva, “then you do indeed want Ulysses home again. Give him his helmet, shield, and a couple of lances, and if he is the man he was when I first knew him in our house, drinking and making merry, he would soon lay his hands about these rascally suitors, were he to stand once more upon his own threshold. He was then coming from Ephyra, where he had been to beg poison for his arrows from Ilus, son of Mermerus. Ilus feared the ever-living gods and would not give him any, but my father let him have some, for he was very fond of him. If Ulysses is the man he then was these suitors will have a short shrift and a sorry wedding.
“But there! It rests with heaven to determine whether he is to return, and take his revenge in his own house or no; I would, however, urge you to set about trying to get rid of these suitors at once. Take my advice, call the Achaean heroes in assembly to-morrow morning—lay your case before them, and call heaven to bear you witness. Bid the suitors take themselves off, each to his own place, and if your mother’s mind is set on marrying again, let her go back to her father, who will find her a husband and provide her with all the marriage gifts that so dear a daughter may expect. As for yourself, let me prevail upon you to take the best ship you can get, with a crew of twenty men, and go in quest of your father who has so long been missing. Some one may tell you something, or (and people often hear things in this way) some heaven-sent message may direct you. First go to Pylos and ask Nestor; thence go on to Sparta and visit Menelaus, for he got home last of all the Achaeans; if you hear that your father is alive and on his way home, you can put up with the waste these suitors will make for yet another twelve months. If on the other hand you hear of his death, come home at once, celebrate his funeral rites with all due pomp, build a barrow to his memory, and make your mother marry again. Then, having done all this, think it well over in your mind how, by fair means or foul, you may kill these suitors in your own house.   Now, however, I must go back to my ship and to my crew, who will be impatient if I keep them waiting longer; think the matter over for yourself, and remember what I have said to you.”
“Sir,” answered Telemachus, “it has been very kind of you to talk to me in this way, as though I were your own son, and I will do all you tell me; I know you want to be getting on with your voyage, but stay a little longer till you have taken a bath and refreshed yourself.
Minerva answered, “Do not try to keep me, for I would be on my way at once. As for any present you may be disposed to make me, keep it till I come again, and I will take it home with me. You shall give me a very good one, and I will give you one of no less value in return.”
With these words she flew away like a bird into the air, but she had given Telemachus courage, and had made him think more than ever about his father. He felt the change, wondered at it, and knew that the stranger had been a god, so he went straight to where the suitors were sitting.
Phemius was still singing, and his hearers sat rapt in silence as he told the sad tale of the return from Troy, and the ills Minerva had laid upon the Achaeans. Penelope, daughter of Icarius, heard his song from her room upstairs, and came down by the great staircase, not alone, but attended by two of her handmaids. When she reached the suitors she stood by one of the bearing posts that supported the roof of the cloisters 8 with a staid maiden on either side of her. She held a veil, moreover, before her face, and was weeping bitterly.
“Phemius,” she cried, “you know many another feat of gods and heroes, such as poets love to celebrate. Sing the suitors some one of these, and let them drink their wine in silence, but cease this sad tale, for it breaks my sorrowful heart, and reminds me of my lost husband whom I mourn ever without ceasing, and whose name was great over all Hellas and middle Argos.” 9
“Mother,” answered Telemachus, “let the bard sing what he has a mind to; bards do not make the ills they sing of; it is Jove, not they, who makes them, and who sends weal or woe upon mankind according to his own good pleasure. This fellow means no harm by singing the ill-fated return of the Danaans, for people always applaud the latest songs most warmly. Make up your mind to it and bear it; Ulysses is not the only man who never came back from Troy, but many another went down as well as he.
She went wondering back into the house, and laid her son’s saying in her heart. Then, going upstairs with her handmaids into her room, she mourned her dear husband till Minerva shed sweet sleep over her eyes. But the suitors were clamorous throughout the covered cloisters 11 , and prayed each one that he might be her bed fellow.
Then Telemachus spoke, “Shameless,” he cried, “and insolent suitors, let us feast at our pleasure now, and let there be no brawling, for it is a rare thing to hear a man with such a divine voice as Phemius has; but in the morning meet me in full assembly that I may give you formal notice to depart, and feast at one another’s houses, turn and turn about, at your own cost. If on the other hand you choose to persist in spunging upon one man, heaven help me, but Jove shall reckon with you in full, and when you fall in my father’s house there shall be no man to avenge you.”
The suitors bit their lips as they heard him, and marvelled at the boldness of his speech. Then, Antinous, son of Eupeithes, said, “The gods seem to have given you lessons in bluster and tall talking; may Jove never grant you to be chief in Ithaca as your father was before you.”
Telemachus answered, “Antinous, do not chide with me, but, god willing, I will be chief too if I can. Is this the worst fate you can think of for me? It is no bad thing to be a chief, for it brings both riches and honour. Still, now that Ulysses is dead there are many great men in Ithaca both old and young, and some other may take the lead among them; nevertheless I will be chief in my own house, and will rule those whom Ulysses has won for me.”
 And now, my good fellow, I want to know about this stranger. What country does he come from? Of what family is he, and where is his estate? Has he brought you news about the return of your father, or was he on business of his own? He seemed a well to do man, but he hurried off so suddenly that he was gone in a moment before we could get to know him.”
“My father is dead and gone,” answered Telemachus, “and even if some rumour reaches me I put no more faith in it now. My mother does indeed sometimes send for a soothsayer and question him, but I give his prophecyings no heed. As for the stranger, he was Mentes, son of Anchialus, chief of the Taphians, an old friend of my father’s.” But in his heart he knew that it had been the goddess.
The suitors then returned to their singing and dancing until the evening; but when night fell upon their pleasuring they went home to bed each in his own abode. 12 Telemachus’s room was high up in a tower 13 that looked on to the outer court; hither, then, he hied, brooding and full of thought. A good old woman, Euryclea, daughter of Ops, the son of Pisenor, went before him with a couple of blazing torches. Laertes had bought her with his own money when she was quite young; he gave the worth of twenty oxen for her, and shewed as much respect to her in his household as he did to his own wedded wife, but he did not take her to his bed for he feared his wife’s resentment. 14 She it was who now lighted Telemachus to his room, and she loved him better than any of the other women in the house did, for she had nursed him when he was a baby. He opened the door of his bed room and sat down upon the bed; as he took off his shirt 15 he gave it to the good old woman, who folded it tidily up, and hung it for him over a peg by his bed side, after which she went out, pulled the door to by a silver catch, and drew the bolt home by means of the strap. 16 But Telemachus as he lay covered with a woollen fleece kept thinking all night through of his intended voyage and of the counsel that Minerva had given him.


9.5: Types of Muscle Fibers
By the end of this section, you will be able to:
- Describe the types of skeletal muscle fibers
- Explain fast and slow muscle fibers
Two criteria to consider when classifying the types of muscle fibers are how fast some fibers contract relative to others, and how fibers produce ATP. Using these criteria, there are three main types of skeletal muscle fibers. Slow oxidative (SO) fibers contract relatively slowly and use aerobic respiration (using oxygen) to produce ATP. Fast oxidative (FO) fibers have fast contractions and primarily use aerobic respiration, but because they may switch to anaerobic respiration (a process called glycolysis that does not require oxygen), can fatigue more quickly than SO fibers. Lastly, fast glycolytic (FG) fibers have fast contractions and primarily use anaerobic glycolysis. The FG fibers fatigue more quickly than the others. Most skeletal muscles in a human contain(s) all three types, although in varying proportions.
The speed of contraction is dependent on how quickly myosin’s ATPase hydrolyzes ATP to produce cross-bridge action. Fast fibers hydrolyze ATP approximately twice as quickly as slow fibers, resulting in much quicker cross-bridge cycling (which pulls the thin filaments toward the center of the sarcomeres at a faster rate). The primary metabolic pathway used by a muscle fiber determines whether the fiber is classified as oxidative or glycolytic. If a fiber primarily produces ATP through aerobic pathways it is oxidative. More ATP can be produced during each metabolic cycle, making the fiber more resistant to fatigue. Glycolytic fibers primarily create ATP through anaerobic glycolysis, which produces less ATP per cycle. As a result, glycolytic fibers fatigue at a quicker rate.
Anatomical distinctions in oxidative fibers reflect the fact that they use and need more oxygen. The oxidative fibers contain many more mitochondria than the glycolytic fibers, because aerobic metabolism, which uses oxygen (O 2 ) in the metabolic pathway, occurs in the mitochondria. The SO fibers possess a large number of mitochondria and are capable of contracting for longer periods because of the large amount of ATP they can produce, but they have a relatively small diameter to facilitate oxygen delivery and thus have fewer myofibrils and do not produce a large amount of tension or power. SO fibers are extensively supplied with blood capillaries to supply O 2 from the red blood cells in the bloodstream. The SO fibers also possess myoglobin, an O 2 -carrying molecule similar to O 2 -carrying hemoglobin in the red blood cells. The myoglobin stores some of the needed O 2 within the fibers themselves (and gives SO fibers their red color). All of these features allow SO fibers to produce large quantities of ATP, which can sustain muscle activity without fatiguing for long periods of time.
The fact that SO fibers can function for long periods without fatiguing makes them useful in maintaining posture, producing isometric contractions, stabilizing bones and joints, and making small movements that happen often but do not require large amounts of energy. They do not produce high tension, and thus they are not used for powerful, fast movements that require high amounts of energy and rapid cross-bridge cycling.
FG fibers primarily use anaerobic glycolysis as their ATP source. They have a large diameter and possess high amounts of glycogen, which is used in glycolysis to generate ATP quickly to produce high levels of tension. Because they do not primarily use aerobic metabolism, they do not possess substantial numbers of mitochondria or significant amounts of myoglobin and therefore have a white color. FG fibers are used to produce rapid, forceful contractions to make quick, powerful movements. These fibers fatigue quickly, permitting them to only be used for short periods. Most muscles possess a mixture of each fiber type. The predominant fiber type in a muscle is determined by the primary function of the muscle.
FO fibers are sometimes called intermediate fibers because they possess characteristics that are intermediate between fast fibers and slow fibers. They hydrolyze ATP relatively quickly, more quickly than SO fibers, and thus can produce relatively high amounts of tension. They are oxidative because they produce ATP aerobically, possess high amounts of mitochondria, and do not fatigue quickly. However, FO fibers do not possess significant myoglobin, giving them a lighter color than the red SO fibers. FO fibers are used primarily for movements, such as walking, that require more energy than postural control but less energy than an explosive movement, such as sprinting. FO fibers are useful for this type of movement because they produce more tension than SO fibers but they are more fatigue-resistant than FG fibers.
Concept Review
The three types of muscle fiber are slow oxidative (SO), fast oxidative (FO) and fast glycolytic (FG). SO fibers use aerobic metabolism to produce low power contractions over long periods and are slow to fatigue. FO fibers use aerobic metabolism to produce ATP but produce higher tension contractions than SO fibers. FG fibers use anaerobic metabolism to produce powerful, high-tension contractions but fatigue quickly.
Review Questions
Q. A sprinter would experience muscle fatigue sooner than a marathon runner due to ________.
A. anaerobic metabolism in the muscles of the sprinter
B. anaerobic metabolism in the muscles of the marathon runner
C. aerobic metabolism in the muscles of the sprinter
D. glycolysis in the muscles of the marathon runner
- Answer
-
Answer: A
Q. Drug X blocks ATP regeneration from ADP and phosphate. How will muscle cells respond to this drug?
A. by absorbing ATP from the bloodstream
B. by using ADP as an energy source
C. by using glycogen as an energy source
D. none of the above
- Answer
-
Answer: D
Critical Thinking Questions
Q. Compare the anatomical differences between SO and FG muscle fibers. How do these differences relate to their function?
- Answer
-
A. Anatomical Differences.
Glossary
- fast glycolytic (FG)
- muscle fiber that primarily uses anaerobic glycolysis
- fast oxidative (FO)
- intermediate muscle fiber that is between slow oxidative and fast glycolytic fibers
- slow oxidative (SO)
- muscle fiber that primarily uses aerobic respiration
Contributors and Attributions
-
OpenStax Anatomy & Physiology (CC BY 4.0). Access for free at https://openstax.org/books/anatomy-and-physiology