First class[change | change source] A first-class lever is a lever where the fulcrum is in between the effort and resistance (the load). Seesaws and crowbars are examples of first class levers. Second class[change | change source] A second-class lever is where the resistance is between the effort and the fulcrum.
This system contains the thalamus, hypothalamus, amygdala, and hippocampus. Brain Stem: Underneath the limbic system is the brain stem. This structure is responsible for basic vital life functions such as breathing, heartbeat, and blood pressure. Scientists say that this is the simplest part of human brains because animals' entire brains, such as reptiles (who appear early on the evolutionary scale) resemble our brain stem.
The hypothalamus regulates emotional responses through its influence on the pituitary gland, skeletal muscular system, and autonomic nervous system. Hypothalamus: Function. The hypothalamus is involved in several functions of the body including: Autonomic Function Control; Endocrine Function Control; Homeostasis; Motor Function Control