ANS

Question 1

where are the preganglionic neurons of the SNS located?

- are they myelinated or not?

Answer 1

intermediolateral column of the thoracic and upper lumbar segments of the spinal cord.

• myelinated

(recall that the PNS preganglionic neurons are located superior to that in the brainstem and posterior to that in the sacral spinal cord)

Question 2

What is the NT released by the preganglionic sympathetic neurons?

Answer 2

Ach

*note: Preganglionic are all nicotinic ACh - excitatory

Question 3

What is the NT released by the postganglionic sympathetic neurons?

Answer 3

○ Sympathetic: Norepinephrine (NE) and Epinephrine

*note: Post Para: Ach

Question 4

Where are the postganglionic sympathetic neurons located?

-is it myelinated or unmyelinated?

Answer 4

ganglia of the sympathetic trunk
(paravertebral chain ganglia aka collateral ganglia)

• unmyelinated

Question 5

What do epinephrine and norepinephrine bind to?

Answer 5

Adrenergic receptors in the blood stream.

• Thus, rather than acting as neurotransmitters, these agents become hormones that regulate the activity of distant target tissues.

Question 6

Vasodilation and vasoconstriction are controlled primarily by the ______ nervous system.

Answer 6

sympathetic

Question 7

What does the NT ACh act on/bind to?

Answer 7

nicotinic cholinergic receptors on post symp and post para neurons

or

muscarinic cholinergic receptors on post para neurons

Question 8

Nicotinic receptor

• what is it?
• what happens when ACh binds?

Answer 8

• ligand-gated, non-selective cation channel (post symp and post para receptor)
• the ion channel that is part of the receptor protein opens and allows rapid movement of Na+ and K+ across the membrane, leading to depolarization and excitation.

Question 9

Muscarinic receptor

• what is it?
• what happens when ACh binds?

Answer 9

• receptors in the cell membrane are linked to a GTP-binding (G) protein.
• When ACh binds to the extracellular site of the muscarinic receptor protein –>
  conformational change occurs within the receptor molecule –>
  “activation” of the G protein coupled to the receptor –>
  The G protein then either stimulates or inhibits other intracellular effectors such as enzymes or ion channels –>
  producing a physiological response.

Question 10

Subtypes of adrenergic receptors

Answer 10

alpha 1
alpha 2
beta 1
beta 2

• good to know for drug targets ;)

Question 11

CV related action of agonist on:
alpha 1
alpha 2

Answer 11

a1: vasoconstriction in skin
a2: Presynaptic inhibition of NE release; some vasoconstriction

Question 12

CV related action of agonist on:
beta 1
beta 2

Answer 12

b1: Increased HR (chronotropy)
b2: Increased HR; vasodilation in skeletal muscle

Question 13

name an agonist:
a1: 
a2: 
b1:
b2:

Answer 13

a1: phenylephrine
a2: Clonidine
b1: Dobutamine
b2: Albuterol

Question 14

drugs that result in sympathetic activation are considered _______

drugs that result in parasympathetic activation are considered ________

Answer 14

sympathomimetic,

parasympathomimetic

Question 15

The activity of the autonomic nervous system is regulated by information coming from _____ _____ and from _______

Answer 15

visceral afferents

higher CNS centers.

Question 16

Example of:
sympathomimetic drug (mimic symp activation)

Answer 16

atropine: Muscarinic M2 antagonist in heart: increases HR

Question 17

Example of:
parasympathomimetic drug (mimic para symp activation)

Answer 17

Propanolol: B- adrenergic antagonist in heart: decreases HR