AUTONOMIC NERVOUS SYSTEM
26 Jan 1995, 30 Jan '97, 29 Jan 98, 3 Feb 03, 31 Jan 05, 4 Feb 08
EM p. 457-, Martini’s 5th: 504-525 Martini’s 6th: 533-552
ANS (p 519) is ultimately controlled by the hypothalamus and enervates smooth & cardiac muscles as well as glands. It acts to ration the body’s energy by shunting blood, altering secretions, etc.
Parasympathetic “Feed or breed” regulates digestive functions, enhancing digestion and absorption.
Sympathetic “Fight or flight” favors physical activity
OVERVIEW: both have 1) a preganglionic neuron in the Central Nervous System
2) a post ganglionic neuron in the Peripheral Nervous System
generalized feature: |
Sympathetic features: (p. 523) (thoracolumbar division) |
Parasympathetic features: (craniosacral division) (p 528) |
preganglionic neuron (in Central NS) |
lateral grey horns |
hypothalamus, brain stem or sacral lateral grey horn |
post ganglionic neuron (Peripheral NS) |
chain ganglia (T1-L2) or splanchnic nerve to collateral ganglion |
terminal ganglia |
post ganglionic neurotransmitter |
noradrenaline |
acetyl choline |
SympatheticPathway (p 522): lateral gray horn, ventral root, white ramus communicans, chain ganglion then one of three pathways:1) gray ramus to spinal nerve 2) chain ganglia to other ganglion and spinal nerve, or 3)unsynapsed via splanchnic nerve to collateral ganglion (plexus) or adrenal medulla. EFFECTS (p 532 &533) |
||
ORGAN |
Sympathetic trait or effect |
Parasympathetic: |
heart, respiration |
increase rate and pressure |
reduce rate and pressure |
arrector pili |
contract |
|
GI tract |
decrease secretion and motility |
stimulate peristalsis, secretion |
bronchioles |
dilate |
constrict |
bladder, anal and urinary sphincters |
relax |
constrict |
pupil |
dilate (radial muscles contract) |
constrict (circular muscles) |
ciliary muscle |
relax (focus far away) |
|
adrenal medulla |
stimulate |
|
sweat glands |
stimulate |
|
GI tract |
inhibit peristalsis |
stimulate peristalsis |
liver |
increase glucose release |
glycogen synthesis |
arteries to skel muscles |
dilate |
|
arteries to viscera and skin, veins |
constrict |
|
lacrimal glands |
|
secrete |
reproductive organs |
male: ejaculation, female: uterus contracts |
male: erection |