Autonomic Nervous System Physiology

Question 1

Where do nerves exit in the Parasympathetic Division?

Answer 1

Brain via cranial nerves and sacral level

Question 2

Where do nerves exit in the Sympathetic Division?

Answer 2

Thoracic and upper lumbar region

Question 3

Do ANS nerves leave the cervical region?

Answer 3

NO

Question 4

Where are parasympathetic ganglion?

Answer 4

NEAR the target organ

Question 5

Where is the ANS controlled?

Answer 5

Hypothalamus in the brain

Question 6

What neurotransmitter does the first synapse release, regardless of sympathetic/parasympathetic division?

Answer 6

Acetylcholine will bind to nictotinic cholinergic receptor and release Na+

Question 7

Na+ is released into the post-synaptic cell and causes what?

Answer 7

Depolarization

Question 8

Neurotransmitter for synapse number 2 in parasympathetic?

Answer 8

Acetylcholine will bind to Muscarinic cholinergic receptor (Gq receptor that increases cellular Ca++ for M1R and M3R)

Question 9

M1R

Answer 9

Increases secretion in salivary glands and parietal cells in stomach

Question 10

M3R

Answer 10

Smooth muscle contraction and increased secretion of exocrine glands (sweat)

Question 11

M2R action

Answer 11

Gi inhibits adenylate cyclase and decreases cAMP

Question 12

M2R function

Answer 12

Cardiac conduction - K+ efflux causes hyperpolarization

Decreases HR and conduction through heart

Question 13

Neurotransmitter for synapse number 2 in sympathetic?

Answer 13

Norepinephrine binds to Adrenergic receptor

Question 14

Alpha1 receptors – Gq increases Ca++

Answer 14

Vasoconstriction, liver increases glycogenolysis/gluconeogenesis, adipose tissue increases lipolysis, lacrimal decreases tear production, dilation of pupil via contraction of radial m. in eye

Question 15

Alpha2 receptors – Gi decreases cAMP

Answer 15

GI contracts sphincters, relax smooth muscle, pancreas increases blood glucose with increased glucagon, platelets increase clotting and activation

Question 16

Beta1 receptor

Answer 16

Heart - SA node increases HR and ventricles increase contractility
Salivary decreases secretions, adipose tissue increases lipolysis (ffa)

Question 17

Beta2 receptors

Answer 17

Bronchodilation, GIGU relaxation, eye affects ciliary muscle that enhances distance vision, liver increases blood glucose

Question 18

Beta3 receptors

Answer 18

White adipose tissue - lipolysis

Brown adipose tissue - heat production

Question 19

Beta receptor action

Answer 19

Stimulates Gs protein, which activates adenylate cyclase and increases cAMP

Question 20

What happens to sympathetic pre-synaptic cells that leave the paravertebral ganglion withOUT synapsing?

Answer 20

They synapse on to a chromaffin cell in the adrenal medulla

Question 21

What happens at the synapse between the adrenal medulla and sympathetic pre-synaptic cell?

Answer 21

Pre-synaptic cell releases acetylcholine that binds to nicotinic cholinergic receptors and causes Na+ depolarization of the cell

Question 22

The chromaffin cells do what?

Answer 22

Release epinephrine into the blood to increase the sympathetic response

Question 23

Explain how a sympathetic signal arrives at the paravertebral column?

Answer 23

Cell bodies in the lateral horn travel out down the anterior root, to the anterior ramus, to the white ramus communicans to the paravertebral column

Question 24

What are the 3 options once a sympathetic signal reaches the paravertebral column?

Answer 24

Synapse
Travel to another spinal level using the paravertebral column
Leave without synapsing using a splanchinc nerve

Question 25

How do sympathetic nerves innervate the skin and sweat glands in the back?

Answer 25

Out the lateral horn, down anterior root and ramus, through the white ramus communicans to the paravertebral ganglion, through the gray ramus communicans back in to the spinal nerve and then down the posterior rami

Question 26

Sympathetic distribution

Answer 26

All over the body - fight or flight

Question 27

Parasympathetic distribution

Answer 27

Localized - rest and digest

Question 28

Where are presynaptic cell bodies housed for the sympathetic division?

Answer 28

Upper lumber and thoracic lateral horns only