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Flashcards in ANS Deck (17):
1

where are the preganglionic neurons of the SNS located?
- are they myelinated or not?

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)

2

What is the NT released by the preganglionic sympathetic neurons?

Ach

*note: Preganglionic are all nicotinic ACh - excitatory

3

What is the NT released by the postganglionic sympathetic neurons?

○ Sympathetic: Norepinephrine (NE) and Epinephrine


*note: Post Para: Ach

4

Where are the postganglionic sympathetic neurons located?
-is it myelinated or unmyelinated?

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

- unmyelinated

5

What do epinephrine and norepinephrine bind to?

Adrenergic receptors in the blood stream.

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

6

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

sympathetic

7

What does the NT ACh act on/bind to?

nicotinic cholinergic receptors on post symp and post para neurons

or

muscarinic cholinergic receptors on post para neurons

8

Nicotinic receptor
- what is it?
- what happens when ACh binds?

- 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.

9

Muscarinic receptor
- what is it?
- what happens when ACh binds?

- 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.

10

Subtypes of adrenergic receptors

alpha 1
alpha 2
beta 1
beta 2

- good to know for drug targets ;)

11

CV related action of agonist on:
alpha 1
alpha 2

a1: vasoconstriction in skin

a2: Presynaptic inhibition of NE release; some vasoconstriction

12

CV related action of agonist on:
beta 1
beta 2

b1: Increased HR (chronotropy)

b2: Increased HR; vasodilation in skeletal muscle

13

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

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

14

drugs that result in sympathetic activation are considered _______

drugs that result in parasympathetic activation are considered ________

sympathomimetic,

parasympathomimetic

15

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

visceral afferents

higher CNS centers.

16

Example of:
sympathomimetic drug (mimic symp activation)

atropine: Muscarinic M2 antagonist in heart: increases HR

17

Example of:
parasympathomimetic drug (mimic para symp activation)

Propanolol: B- adrenergic antagonist in heart: decreases HR