Autonomic Nervous System Physiology

Question 1

What is the universal neurotransmitter for preganglionic neurons in the ANS?

Answer 1

Acetylcholine

Question 2

Which has a higher preganglionic to postganglionic ratio, parasympathetic or sympathetic?

Answer 2

The sympathetic has a higher ratio (10:1) than the parasympathetic (3:1)

Question 3

T or F?

The parasymphatethic has ganglia located near the spinal cord

Answer 3

False

The sympathetic has ganglia located near the spinal cord.

The parasymphthetic has ganglia located near the target organs.

Question 4

T or F?

The postganglionic parasympathetic neurons release acetylcholine and the postganglionic sympathetic neurons release epinephrine and norepinephrine.

Answer 4

True

Sorry if these are too simple, I just wanted to do a quick refresher for myself.

Question 5

What makes the adrenal medulla special in regards to the sympathetic nervous system?

Answer 5

The postganglionic cells located here secrete epinephrine and norepinephrine into the blood stream to bind to adrenergic receptors. Thus, these act as hormones as opposed to neurotransmitters.

Question 6

T or F?

The sympathetic nervous system primarily controls vasodilation and vasoconstriction

Answer 6

True.

Increased sympathetic leads to vasoconstriction as well as increased heart rate and force of contraction

Question 7

Which 4 cranial nerves are part of the parasympathetic nervous system?

Answer 7

III (oculomotor), VII (facial), IX (glosspharyngeal), X (vagus)

Question 8

Which has longer postganglionic axons, sympathetic or parasympathetic?

Answer 8

Sympathetic.

Question 9

By which mechanism are neurotransmitters (Ach and Norepi) released from postganglionic neurons of the ANS?

Answer 9

Exocytosis

Question 10

Where are nicotinic receptors primarily located?

Answer 10

They are primarily present in the cell bodies of postganglionic neurons of the autonomic ganglia

Question 11

Where are the muscarinic receptors primarily located?

Answer 11

Muscarinic receptors are present on the effector cells of cardiac muscle, smooth muscle, and glands

Question 12

T or F?

The nicotinic receptor is a ligand-gated, selective channel

Answer 12

False.

It’s a ligand-gated, non-selective channel that opens when Ach binds it and allows for Na and K to move across the membrane, leading to depolarization and excitation.

Question 13

What kind of proteins are associated with muscarinic receptors in the cell membrane?

Answer 13

G proteins. They carry out a lot of different physiological functions within the cell.

Question 14

T or F?

There are 2 types of muscarinic receptors

Answer 14

False.

There are 5 subtypes. That’s why there’s such variety in what can happen when Ach binds to a muscarinic receptor and activates the G protein.

Question 15

How many different subtypes of adrenergic receptors are there?

T or F?

Norepinephrine (NE) activates all of the adrenergic receptors

Answer 15

There are 4 types (alpha 1, alpha 2, beta 1, beta 2)

False.

NE only activates alpha 1, alpha 2, and beta 1. Epinephrine activates all 4.

Question 16

T or F?

Beta blockers (propanalol) are good treatment for hypertension and coronary artery disease

Answer 16

True.

Epinephrine or a more selective B2 blocker would also be good for people w/ asthma who are experiencing bronchoconstriction.

Question 17

Give the CV related action, an agonist (sympathomimetic) and antagonist (parasympathomimetic) of the adrenergic receptor: Alpha 1

Answer 17

Vasoconstriction in skin.

Agonist: Phenylephrine

Antagonist: Doxazosin

Question 18

Give the CV related action, an agonist (sympathomimetic) and antagonist (parasympathomimetic) of the adrenergic receptor:

Alpha 2

Answer 18

CV: Presynaptic inhibition of NE release, some vasoconstriction

Agonist: Clonidine

Antagonist: Trazodone

Question 19

Give the CV related action, an agonist (sympathomimetic) and antagonist (parasympathomimetic) of the adrenergic receptor:

Beta 1

Answer 19

CV: Increased heart rate

Agonist: Dobutamine

Antagonist: Atenolol

Question 20

Give the CV related action, an agonist (sympathomimetic) and antagonist (parasympathomimetic) of the adrenergic receptor:

Beta 2

Answer 20

CV: Increased heart rate. Vasodilation in skeletal muscle

Agonist: Albuterol

Antagonist: Butaxamine

Question 21

In the baroreceptor reflex, what response is expected when you have low blood pressure?

Answer 21

A relative increase in sympathetic output. The opposite is also true.

Question 22

What is the effect in the heart if there is increased Ach release (ie increased parasympathetic)

Answer 22

The heart will beat slower with less force.

Question 23

Why is the hypothalamus so important in homeostasis?

Answer 23

It’s the head control ganglion.

It controls different responses/reflexes of the autonomic nervous system.

It also controls release of hormones via the pituitary gland (vasopressin release which helps to control blood pressure).

The hypothalamus coordinates the ANS and humoral responses.

Question 24

What’s the effect of vasopressin?

Answer 24

It causes increased vasoconstriction as well as increased water retention in the kidneys in response to low blood pressure.

Question 25

What do renin and angiotensin do in response to low blood pressure?

Answer 25

Renin activates angiotensin to angiotensin I which then goes on to become angiotensis II which constricts blood vessels, increases water retention in the kidneys, and activates neurons in subformical organs.

Controlled by the hypothalamus.