is a lateral view of the left side of a human brain.
the basis of their phylogenetic and ontogenetic origin, neuroanatomists generally
classify the structures of the brain as shown below, from the most evolved to
the most primitive.
(Place your cursor over the
name of each structure to see where it is located on the sagittal view of the
listed below are often considered to constitute the limbic system. This
system is involved in olfaction, emotions, learning,
and memory. The limbic system was introduced as a concept by Paul MacLean
in 1952 and was long considered the seat of the emotions. Though some of the structures
included in this system are in fact involved in some emotional responses, we now
know that it does not correspond exactly to any of the multiple emotional systems
in the brain.
autonomic nervous system is controlled mainly by the hypothalamus and is in
turn divided into two sets of nerves: the sympathetic and parasympathetic nervous
systems. Each of these two systems has a distinct anatomical location and communicates
with its target organs through other neurons located in ganglia.
SYMPATHETIC NERVOUS SYSTEM
sympathetic nervous system goes into action to prepare the organism for physical
or mental activity. When the organism faces a major stressor, it is the sympathetic
nervous system that orchestrates the fight-or-flight
response. It dilates the bronchi and the pupils, accelerates heart rate and
respiration, and increases perspiration and arterial blood pressure, but reduces
digestive activity. Two neurotransmitters are primarily associated with this system:
epinephrine and norepinephrine.
PARASYMPATHETIC NERVOUS SYSTEM
activation of the parasympathetic nervous system causes a general slowdown in
the body’s functions in order to conserve energy. Whatever was dilated,
accelerated, or increased by the sympathetic nervous system is contracted, decelerated,
or decreased by the parasympathetic nervous system. The only things that the parasympathetic
nervous system augments are digestive functions and sexual appetite. One neurotransmitter
is primarily associated with this system: acetylcholine.