The autonomic nervous system

Question 1

How does viagra facilitate erections?

Answer 1

• Increases NO
• NO binds with guanylyl cyclase receptors
• cGMP produced
• cGMP causes smooth muscle relaxation, causing vasodilation and compressing the venous outflow

Question 2

The ANS is a component of the:

• Afferent nervous system
• Efferent nervous system

Answer 2

Efferent nervous system

Efferent motor activity etc.

Question 3

What is the enteric nervous system?

Answer 3

The third division of the ANS is a system of ANS neurons in the walls of the gut that regulate gut activities (motor, secretory etc.)

Question 4

True or false. The ANS can innervate skeletal muscle

Answer 4

False. It can only innervate:

• Cardiac
• Exocrine
• Smooth muscle

Question 5

Describe post ganglionic axons in the PNS and SNS

Answer 5

PNS: Short post ganglionic axons

SNS: short PRE ganglionic axons. Paravertibral ganglia chain

Question 6

The SNS uses which neurotransmitters for the following:

• Sweat glands
• Cardiac smooth muscle
• Kidney

Answer 6

SNS

• Sweat glands (ACh - exception!)
• Cardiac smooth muscle (NA)
• Kidney (NA)

Question 7

The parasympathetic nervous system always uses which neurotransmitter?

Answer 7

ACh

Question 8

In the Parasympathetic nervous system, acetylcholine binds to ____ receptors at ganglia and _____ receptors at end organs

Answer 8

In the Parasympathetic nervous system, acetylcholine binds to nicotinic receptors at ganglia and muscarinic receptors at end organs

Question 9

Define miosis and mydriasis

Answer 9

Miosis: Pupil constriction (acetylcholine)

Mydriasis: pupil dilation (NA)

Question 10

What does botulin toxin do?

Answer 10

Inhibits the release of ACh

Question 11

How do muscarinic agonists in bronchial tubes make it harder to breathe? (give mechanism)

Answer 11

• M3 receptor stimulated
• Gq protein activates PLC
• PLC hydrolyzes PIP2 to form IP3 and DAG
• Calcium released and binds with calmodulin, stimulating myosin light chain kinase and causing contraction

Question 12

Give three uses of direct muscarinic agonists

Answer 12

• Stimulate tone after surgery
• Increase gut motility
• Constrict ciliary muscle of eye and promote aqueous humor drainage in glaucoma

Question 13

List 5 possible side effects of muscarinic agonists

Answer 13

• Stimulation of all muscarinic receptors
• GI disturbances (eg. nausea/vomiting)
• CNS effects (sedation)
• Lower HR (Bradycardia).
• Salivation and bronchoconstriction

Question 14

Which types of cholinesterase inhibitors are used therapeutically?

Answer 14

Reversible ones

Question 15

Somes uses of reversible cholinesterase inhibitors: (3)

Answer 15

• Stimulate tone in bladder and gut
• Treat myasthenia gravis (muscle fatigue)
• Alzheimers (depressed ACh transmission in brain)

Question 16

What can muscarinic antagonists do therapeutically?

Answer 16

• Speed the heart rate (eg. atropine)
• Block PNS constriction in airways
• Dilate pupil for eye exam
• Overactive bladder
• Motion sickness

Question 17

What do nicotinic antagonists do?

Answer 17

• Block nicotinic nerve receptors at autonomic ganglia

- Block NMJ transmission

Question 18

What are the two major types of neuromuscular blockers?

Answer 18

• Depolarizing (non-competitive) antagonists (cannot be overcome with AChE inhibitor).
• Non-depolarizing (competitive) antagonists (can be overcome with AChE inhibitor)

Both used for Paralysis during surgery.

Question 19

REMEMBER

Answer 19

NEED TO MAKE ANS III CARDS