Physiology of ANS

Question 1

Where are the inputs of the autonomic nervous system processed?

Answer 1

in the CNS, particularly the hypothalamus

Question 2

What is the neurotransmitter used by both the sympathetic and parasympathetic nervous systems at the first synapse?

Answer 2

Ach

Question 3

What type of receptors are on the post-ganglionic cells of the first synapse of both the sympathetic and parasympathetic nervous systems?

Answer 3

nicotinic

Question 4

What type of receptor is used at the second synapse for the sympathetic nervous system?

Answer 4

adrenergic

Question 5

What type of receptor is used at the second synapse for the parasympathetic nervous system?

Answer 5

muscarinic

Question 6

What type of receptors are the adrenergic and muscarinic receptors?

Answer 6

serpentine super family of receptors

Question 7

Where do the impulses exit from the CNS in the sympathetic response?

Answer 7

Thoracic and lumbar regions

Question 8

Where do the impulses exit from the CNS in the parasympathetic response?

Answer 8

Cranial and sacral

Question 9

Where is the location of the second synapse in the sympathetic response?

Answer 9

sympathetic chain

Question 10

Where is the location of the second synapse in the parasympathetic response?

Answer 10

at the target organ

Question 11

How do the lengths of the pre-ganglionic fiber differ between sympathetic and parasympathetic response (when referring to the 2nd synapse)?

Answer 11

Sympathetic - short

Parasympathetic - long

Question 12

How do the lengths of the post-ganglionic fiber differ between sympathetic and parasympathetic response (when referring to the 2nd synapse)?

Answer 12

Sympathetic - long

Parasympathetic - short

Question 13

What are the specific receptors for the parasympathetic response?

Answer 13

M1R, M2R, M3R

nobody cares about 4 or 5

Question 14

What are the specific receptors for the sympathetic response?

Answer 14

Alpha-1, Alpha-2

Beta-1, Beta-2, Beta-3

Question 15

What is the parasympathetic response when an M1R is activated?

Answer 15

increased salivation

increased GI secretion

Question 16

What is the parasympathetic response when an M2R is activated?

Answer 16

K+ channels open = cell re-/hyperpolarization

HR slows

Question 17

What is the parasympathetic response when an M3R is activated?

Answer 17

inceased smooth muscle ctx

• GI motility
• bronchi constriction

increased exocrine gland secretion
-lacrimal, sweat

ciliary M. relaxes = pupil constriction (round lens)

Question 18

What is the sympathetic response when an alpha-1 receptor is activated?

Answer 18

blood vessel smooth muscle ctx = BP increases
increased gluconeogenesis, increased glycogenolysis
increased lipolysis

Question 19

What is the sympathetic response when an alpha-2 receptor is activated?

Answer 19

GI sphincter constriction
pancreas increases glucagon, decreases insulin
increase in platelets = clotting

Question 20

What is the sympathetic response when a beta-1 receptor is activated?

Answer 20

HR increases
cardiac muscle ctx strength increases
decreased salivation
increases lipolysis

Question 21

What is the sympathetic response when a beta-2 receptor is activated?

Answer 21

bronchiole smooth muscle dilation
GI smooth muscle relaxation
increased glycogenolysis and gluconeogenesis
increased lipolysis

Question 22

What is the sympathetic response when a beta-3 receptor is activated?

Answer 22

adipose tissue (white) = increased lipolysis
adipose tissue (brown) = increased thermogenesis

Question 23

What are chromaffin cells?

Answer 23

cells in the adrenal medulla that make and secrete epinephrine

Question 24

How is the adrenal medulla involved in the sympathetic response?

Answer 24

some sympathetic axons synapse in the adrenal medulla as their 1st synapse (instead of the paravertebral ganglion)

Ach then binds to nicotinic receptors on chromaffin cells which release epinephrine

Question 25

Name some key aspects of the “fight or flight” response.

Answer 25

• need lots of oxygen to get it to the muscles
• heart is pumping hard and fast
• limited digestion
• pupil dilates and lens flattens
• skeletal muscle, lung/heart/ brain blood vessels dilate
• GI and skin blood vessels constrict