The autonomic nervous system is a
part of the nervous system that unconsciously regulates bodily functions such
as the heart rate, digestion, respiratory rate, pupillary response and
urination. The autonomic nervous system has two divisions which are the
sympathetic and the parasympathetic nervous system. The sympathetic nervous
system constricts blood vessels and enhances both the heart rate and blood
pressure while the parasympathetic nervous system slows the heart rate, enhances
intestinal and gland activity, and relaxes sphincter muscles.
Limbic system is known to be an area of the brain that is
involved in memory and emotion.They interact with autonomic nervous system and
reticular activating system to assist the body in process emotions. Thus, the structures
of the limbic system includes amygdala, mammillary bodies, the hippocampus and
cingulate gyrus.
Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.
<span>The average heart rate is the number of heart beats counted in 15 seconds divided by 15 seconds. The instantaneous heart rate is the time it takes for a single heart beat. Since the heart can beat at varying rates, these values are not necessarily the same.</span>
