L1 Intro to ANS (Exam #1)

Question 1

In parasympathetic, ____ preganglionic fibers release ____, acting on ____ receptors

Answer 1

PARASYMPATHETIC

Long preganglionic release ACh onto N receptors

Question 2

In parasympathetic, ____ postganglionic fibers release ____, acting on ____ receptors

Answer 2

PARASYMPATHETIC

Short postganglionic release ACh on M receptors

Question 3

In sympathetic, ____ preganglionic fibers release ____, acting on ____ receptors

Answer 3

SYMPATHETIC

Short preganglionic release ACh on N receptors

Question 4

In sympathetic, ____ postganglionic fibers release ____, acting on ____ receptors

Answer 4

SYMPATHETIC
Long postganglionic release NE onto a1 or b1 receptors

• Sometimes DA or ACh

Question 5

What is released from the adrenal medulla, and to where?

Answer 5

Epi or NE are released from the adrenal medulla directly into circulation

Question 6

What is released from sympathetic neurons innervating sweat glands? What type of receptor do they act on?

Answer 6

ACh onto M receptors

Question 7

What is released from sympathetic neurons innervating renal vasculature? What type of receptor do they act on?

Answer 7

DA onto D1 receptors

Question 8

Which two receptor types are the ONLY inhibitory?

Answer 8

• a2

- M2

Question 9

With cholinergic transmission, after ACh is released from its storage vesicle by an AP, what two receptor types can it bind to, and what is the response of each?

Answer 9

• Presynaptic receptors (N): inhibits release of more ACh (negative feedback)
• Postsynaptic receptors (M): cholinergic response

Question 10

During cholinergic transmission, what is the enzyme that synthesizes ACh? What is the enzyme that degrades ACh?

Answer 10

• Synthesized by ChAT (choline acetyltransferase)

- Degraded by AChE (acetyl-cholinesterase)

Question 11

How does Botox affect cholinergic transmission?

Answer 11

Inhibits cholinergic vesicle release, resulting in low ACh levels

Question 12

How do muscarinic antagonists affect cholinergic transmission?

Answer 12

Inhibit activation of muscarinic receptors on postganglionic terminal

Question 13

How do cholinesterase inhibitors affect cholinergic transmission?

Answer 13

Inhibits AChE, resulting in high ACh levels in synaptic cleft

Question 14

With adrenergic transmission, what is the rate limiting step?

Answer 14

After tyrosine enters the nerve terminal, it is converted to L-DOPA by tyrosine hydroxylase

Question 15

With adrenergic transmission, after tyrosine is converted to L-DOPA by tyrosine hydroxylase, what two neurotransmitters can it be converted into?

Answer 15

1. L-DOPA to DA

2. L-DOPA to DA to NE

Question 16

With adrenergic transmission, what type of transporter is used to reuptake NE? What two drugs act on this transporter, inhibiting the reuptake of NE - what is the result?

Answer 16

NET

- Cocaine and antidepressants block NET, resulting in high NE levels in synaptic cleft

Question 17

How do Amphetamines affect adrenergic transmission?

Answer 17

Displaces/increases levels of NE in nerve terminal, so more NE is released, resulting in high NE levels in synaptic cleft

Question 18

Which three drugs require an INTACT nerve terminal to work?

What drug type is an exception to this, and why?

Answer 18

• Cocaine
• Antidepressants
• Amphetamines

Adrenergic antagonists inhibit activation of adrenergic receptors

Question 19

In which two systems does sympathetic NS dominate?

Answer 19

• Blood vessels

- Skin/sweat glands

Question 20

Which receptors are activated by NE? Which receptors are activated by Epi?

Answer 20

• NE: a1, b1

- Epi: a1, b1, b2

Question 21

For sympathetic stimulation of blood vessels, what neurotransmitter and receptor type is often used, and what is the result?

Answer 21

NE acts on a1 receptors

- Vasoconstriction

Question 22

For sympathetic stimulation of blood vessels, when Epi is released in low doses, what receptor does it act on and what is the result? In high doses?

With what type of blood vessels is this an exception, where Epi = NE?

Answer 22

Low Epi acts on b2 receptors
- Vasodilation

High Epi acts on a1 receptors
- Vasoconstriction

In skin and reservoir veins, Epi = NE so it acts mostly on a1 receptors to vasoconstrict

Question 23

On what type of blood vessels does DA act? When DA is released in low doses, what receptor does it act on and what is the result? In high doses?

Answer 23

Renal vasculature

Low DA acts on D1 receptors
- Vasodilation

High DA acts on a1 receptors
- Vasoconstriction

Question 24

What is mydriasis?

Answer 24

Pupil dilation

Question 25

What is miosis?

Answer 25

Pupil constriction