Download BIOL 241 Autonomic Nervous System 1 I. Visceral Reflexes A. All

BIOL 241
Autonomic Nervous System 1
I. Visceral Reflexes
A. All effectors except skeletal muscles
1. glands
2. cardiac muscle
3. smooth muscle
B. Autonomic neurons
1. not somatic
2. requires two neurons
a. preganglionic
b. postganglionic
C. Somatic vs. visceral effectors
1. skeletal muscle (somatic)
2. visceral effectors
a. heartb. smooth musclec. ANS activity
d. denervation hypersensitivity
D. Receptors
II. ANS Divisions
A. Sympathetic division
1. preparation for physical activity
a. increase in heart rate and blood pressure
b. dilation of respiratory passages
c. sweat
d. inhibits some “resting” functions
2. cell bodies in lateral horns of spinal gray (T1-L2)
3. axons emerge from ventral roots ----> ganglia
a. white communicating rami
b. sympathetic chain ganglia
-Mass activation
c. gray rami
d. collateral ganglia (below diaphragm)
near target organs
celiac, superior mesenteric, inferior mesenteric
splanchnic nerves
e. pregangs will synapse w/ postgangs in either chain or collateral ganglia
f. all sympathetic postgangs arise from ganglia
4. Adrenal glands
a. cortex -steroids
b. medulla - derived from neural crest
modified symp. ganglion
epinephrine and norepinephrine
some dopamine
B. Parasympathetic division
1. vegetative activities
2. reduces heart rate and respiration
3. some cell bodies in brainstem nuclei of CN’s
III - midbrain to ciliary ganglion (ciliary muscle, pupillary constrictors)
VII - pons to pterygopalatine and submandibular ganglia
IX - medulla to otic ganglion via tympanic nerve
X - medulla to several organs
4. some pregangs arise from S2-S4 (pelvic splanchnics)
5. pregangs not normally traveling with sacral spinal nerves
6. pregangs travel to terminal ganglia
a. near target organs
b. may be in walls of target organs
c. long pregangs, short postgangs