Functions of the sympathetic nervous system
➢ He leaves the house and it being winter, a cold wind causes his cheeks to blanche
➢ He has to cross a busy street without the aid of traffic lights and his palms start to sweat
The Functions of the Autonomic Nervous System
The functions of the parasympathetic and sympathetic nervous systems can perhaps best be understood by visualizing a male student who wakes slowly and quietly one morning from a deep, refreshing sleep. The first functions belong to the parasympathetic nervous system.
close vision ➢ He goes to the bathroom and empties his bladder ➢ He smells bacon cooking and starts to salivate ➢ As he eats, gastric and later intestinal juices flow ➢ Peristalsis begins in the stomach ➢ Peristalsis reaches the colon and he empties his
➢ A car brushes by close to him and he feels the hair on the back of his neck stand up
➢ He makes a dash for it and his heart start to pound ➢ His blood pressure rises ➢ He reaches the other side of the road, gasping for
bowels ➢ To permit emptying the internal anal sphincter must
relax
The opposite actions to the foregoing are produced by the sympathetic nervous system, but we can easily carry our student further.
Functions of the parasympathetic nervous system
➢ His heart is beating slowly ➢ He may awake with an erection ➢ He turns on the light causing his pupils to constrict ➢ The bright light causes tears to flow ➢ He looks at his watch and the eyes accommodate for
breath；his bronchi therefore will dilate ➢ The last item is difficult to work into our little scenario；
the muscular contractions of orgasm are sympathetic
The Functions of the Autonomic Nervous System
The functions of the parasympathetic nerence
Sleep
Sex
The functions of the sympathetic nervous system (3F)
Fight
Flight
Fright