Functional Aspects of the Autonomic Nervous System Flashcards Preview

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Flashcards in Functional Aspects of the Autonomic Nervous System Deck (52)
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1
Q

What is the major pathway for information transmission from the CNS to the involuntary effector tissues (smooth muscle, cardiac muscle, and exocrine glands)?

A

The motor efferent portion of the ANS

2
Q

What is the meaning of Adrenergic?

A

A nerve ending that releases norepi as the primary transmitter

3
Q

What is meant by adrenergic receptor?

A

A receptor that binds and is activated by one of the catecholamine transmitters or hormones such as; epi, norepi, dopamine and related drugs

4
Q

What is meant by cholinergic?

A

Nerve ending that releases acetylcholine; also a synapse where the primary transmitter is acetylcholine

5
Q

What is meant by homeostatic reflex?

A

A compensatory mechanism for maintaining a body function at a predetermined level

6
Q

What is the primary transmitter in all autonomic ganglia and at the synapses between parasympathetic postganglionc neurons and their effector cells

A

Acetylcholine

7
Q

What is the rate limiting step in the synthesis and storage of Acetylcholine?

A

The transport of into the nerve terminal

8
Q

What drug can inhibit the transport of Acetylcholine into its nerve terminals after synthesis?

A

Hemicholinium

9
Q

What is the transporter responsible for transporting acetylcholine into its vesicles for storage?

A

Vesicle associated transporter VAT

10
Q

What drug inhibits VAT?

A

Vesamicol

11
Q

What ion mediates the release of acetylcholine from its vesicles in nerve endings?

A

Calcium entry through channels and triggering of an interaction between SNARE proteins and t-SNARE

12
Q

How does Botulinum toxin work?

A

Enzymatically alters synapto-brevin or one of the other docking or fusion proteins to prevent the release process of acetylcholine

13
Q

How is the Acetylcholine action terminated?

A

ACh is metabolized to acetate and choline by Acetylcholinesterase in synaptic cleft

14
Q

What is the primary transmitter at sympathetic postganglionic neuron effector cell synapses in most tissues?

A

Norepi

15
Q

What function does serve in Renal blood vessels?

A

Vasodilator transmitter

16
Q

What is the rate limiting step and enzyme in the synthesis of Norepi and Dopamine?

A

The hydroxylation of Tyrosine to DOPA by Tyrosine Hydroxylase

17
Q

How can tyrosine hydroxylase be inhibited?

A

By Metyrosine

18
Q

What molecule transports Norepi and Dopamine into their vesicles?

A

VMAT

19
Q

What is (MOA) Monoamine Oxidase?

A

A molecule which is present on mitochondria in the adrenergic nerve ending that inactivates a portion of the dopamine and norepi in the cytoplasm

20
Q

What effect does MOA inhibitors have?

A

Inhipits the breakdown of Norepi and Dopamine and othe monoamines in nerve endings

21
Q

What drug inhibits VMAT?

A

Reserpine

22
Q

What mechanism is responsible for the release of Norepi and Dopamine?

A

Same as ACh, calcium dependent

23
Q

What mechanisms are responsible for the termination of action of Norepi and Dopamine.

A

Diffusion and reuptake (especially uptake 1) by transporters NET and DAT

24
Q

What does Guanethidine do?

A

Blocks norepinephrine release blocking sympathetic but not parasypathetic functions

25
Q

What are Muscarine receptors?

A

These receptors respond to Muscarine as well as acetylcholine, the effect of these receptors resemble those of postganglionic parasympathetic nerve stimulation.

26
Q

Where are muscarinic receptors mostly located?

A

Primarily on autonomic effector cells incuding heart vascular endothelium smooth muscle and presynaptic nerve terminals

27
Q

What do all muscarinic receptors have in common?

A

Are G-coupled receptors

28
Q

What are the nicotinic receptors?

A

These receptors are located on Na-K ion channels and respond to acetylcholine and nicotine but not Muscarine by opening the channel

29
Q

Where are the Nicotinic receptors located?

A

In ganglia and in Skeletal muscle

30
Q

What are the Adrenoceptors?

A
  1. Alpha

2. Beta

31
Q

Where are Alpha receptors located?

A

On vascular smooth muscle, presynaptic nerve terminals, blood platelets, fat cells and neurons in the brain

32
Q

Where are Beta receptors located?

A

Mostly on smooth muscle, cardiac muscle some presynaptic nerve terminals and lipocytes

33
Q

What do all the subtypes of Beta receptors have in common?

A

All us the same G-coupling protein

34
Q

Where are Dopamine receptors most found/important?

A

Renal and Splanchnic vessels and the Brain

35
Q

Which is the most important subtype of Dopamine receptors?

A

D1

36
Q

What is the purpose of the release of ATP and substance P with ACh?

A

Modulation

37
Q

What is an presynaptic AUTORECEPTOR?

A

is a receptor for the Ligand that is being released from the presynaptic nerve ending at a cholinergic synapse it would be a Muscarinic receptor and it essentially turns off action

38
Q

What is a presynaptic Heteroreceptor?

A

Regulatory receptor that responds to substance other than the transmitter itself

39
Q

Drugs which are not impacted by Acetylcholinesterase inhibitor

A

Carbachol Chloride

Bethanecol chloride

40
Q

How do Cocaine, and Tricyclic antidepressants work?

A

Inhibit uptake of Norepi from synaptic cleft by blocking NET

41
Q

How does Bretylium guanethidine work?

A

Inhibiting fusion of transmitter containing vesicles with the end plate by blocking VAMPs in Adrenergic fibres

42
Q

Where are Beta-2 Adrenergic receptors mostly found?

A

Lung

Vasculature of Skeletal Muscle

43
Q

What is the specificity of the transmitter Epi?

A

A-a=A-2;B-1=B-2

44
Q

Which drug causes a widening of the pulse pressure?

A

Epinephrine

45
Q

Why does Pulse pressure widen when Epi is given?

A

Due to stimulation of Beta-2 which causes vasodilation and pressure is falling

46
Q

What is the difference in Calcium dependency for Myocyte contraction vs Smooth muscle of vasculature?

A

In Cardiac cells its the release of Ca2+ from SR where as in smooth muscle its the influx of Calcium from outside the ell that triggers the action

47
Q

What is the effect of activation of the B-2 receptors in Bronchio Smooth muscle?

A

Relaxation of the smooth muscle

48
Q

What is Tachyphylaxis?

A

Loss of activity of a drug

49
Q

Which receptors are stimulated in response to Hypoglycemia?

A

Alpha-1 and Beta-2

50
Q

In which type Diabetes would you expect non-selective Beta Blockers to delay recovery from hypoglycemia?

A

Type -1

51
Q

Is there Cholinergic innervation of the Blood vessels?

A

No

52
Q

What is the effect of Mucarinic agents on the vasculature then?

A

Promote release of NO which causes Vasodilation