ANS part 2

Question 1

what is the origin of the PNS?

Answer 1

craniosacral

Question 2

What does the PNS target?

Answer 2

smooth muscle, cardiac muscle, and glands

Question 3

What are the effects of stimulation of the PNS?

Answer 3

Salivation
Lacrimation
Stimulate digestion
Urination
Defecation
Pupillary constriction
Vasomotor control
Bronchial control

Question 4

What is the main nerve of the PNS?

Answer 4

Vagus (wandering - because innervates a lot of things - thoracic and abdominal structures)

Question 5

What is the origin of the vagus nerve?

Answer 5

brainstem

Question 6

True or False. The vagus nerve innervates all nerves of the larynx.

Answer 6

FALSE. The vagus nerve innervates all nerves of the larynx EXCEPT cricothyroid (superior laryngeal nerve)

Question 7

If both nerves paralyzed, what might we see in regards to the vocal cords?

Answer 7

stridor/laryngeal obstruction

Question 8

What are the two types of cholinergic receptors?

Answer 8

nicotinic and muscarinic

Question 9

True or False. ACh can be found at the presynaptic nerves in both SNS and PNS.

Answer 9

TRUE. PNS has ACh at both pre and postsynaptic nerves while SNS only has ACh at presynaptic nerves.

Question 10

What happens if we block acetylcholinesterase?

Answer 10

Huge parasympathetic outflow (give anticholinergics to block/counteract)

Question 11

What are the steps causing release of ACh from the vesicles?

Answer 11

depolarization of nerve-> influx of Ca2+ ->vesicular exocytosis -> NT release in synapse

Question 12

What effect does Botulism Toxin A have on the PNS?

Answer 12

binds to vesicles and prevents exocytosis (causes paralysis and PNS derangements)

Question 13

How is termination of ACh carried out?

Answer 13

1. reuptake of active ACh
2. hydrolysis via acetylcholinesterase to acetate and choline
3. diffusion away from synapse (minimal)

Question 14

How does reuptake of ACh occur?

Answer 14

by high affinity NaCl co-transport coupled to Na/K ATPase

Question 15

What are some of the acetylcholinesterase inhibitors (anticholinesterase)?

Answer 15

neostigmine, endrophonium, pyridostigmine, physostigmine

Question 16

Where are nicotinic receptors located?

Answer 16

NMJ, autonomic ganglia (pre synaptic SNS and PNS)

Question 17

Where does ACh bind on the nicotinic receptor?

Answer 17

the alpha subunit

Question 18

What is the function of the M1 receptor?

Answer 18

autonomic ganglia and CNS

Question 19

What is the function of the M2 receptor?

Answer 19

supraventricular cardiac (bradycardia and decr contractility)

Question 20

What is the function of the M3 receptor?

Answer 20

smooth muscle and glands

Question 21

What are the steps to activation of the PNS via nicotinic receptors?

Answer 21

stimulation -> increased Na/K permeability -> depolarization

Question 22

What are the steps to activation of the PNS via muscarinic receptors?

Answer 22

stimulate G-protein -> activate phospholipase C -> breakdown fatty acids into IP3 and DAG -> increased Ca 2+ released from sarcoplasmic reticulum

Question 23

True or False. ACh binding always leads to smooth muscle constraction due to increased Ca2+

Answer 23

FALSE. ACh increases nitric oxide (NO) release from endothelial cells. NO is a potent vasodilator.

Question 24

What is a cholinergic crisis?

Answer 24

uncontrolled upregulation of PNS

causes mydriasis, miosis, perspiration, salivation, bronchoconstriction, bronchial secretions, flaccid paralysis, respiratory failure

**SLUDGE BB

Question 25

What is the treatment of a cholinergic crisis?

Answer 25

ANTICHOLINERGICS (atropine/glycopyrrolate)