Autonomic Nervous System II

Question 1

In terms of the sympathetic nervous system, what outflow does it have?

Answer 1

It has a thoraco - lumbar outflow.

Question 2

In terms of pre - ganglionic fibres and the main terminal messenger, what is it for the sympathetic nervous system?

Answer 2

SHORT pre - ganglionic fibres.

NORADRENALINE is the main terminal messenger.

Question 3

In terms of the parasympathetic nervous system, what outflow does it have?

Answer 3

It has a sacrro - cranial outflow.

Question 4

In terms of pre - ganglionic fibres and the main terminal messenger, what is it for the parasympathetic nervous system?

Answer 4

LONG pre - ganglionic fibres.

ACETYLCHOLINE is the main terminal messenger.

Question 5

What are the receptors for acetylcholine?

Answer 5

Nicotinic Receptors.

Question 6

What happens when acetylcholine binds to nicotinic receptors?

Answer 6

Binding of acetylcholine causes an ion path to OPEN.

Question 7

In terms of the sympathetic nervous system, what is the category given for the receptors?

Answer 7

ADRENORECEPTORS.

Alpha 1 and 2 // Beta 1 and 2 and 3.

Question 8

In terms of the parasympathetic nervous system, what is the category given for the receptors?

Answer 8

MUSCARINIC RECEPTORS.

M1 TO M5.

Question 9

What substance does adrenoreceptors release?

Answer 9

Releases noradrenaline.

Question 10

What substance does muscarinic receptors release?

Answer 10

Releases acetylcholine.

Question 11

How many transmembrane domains are there for G - protein coupled receptors?

Answer 11

There are 7 transmembrane domains.

Question 12

In terms of alpha Gs, what does it do in terms of adenylate cyclase and cAMP?

Answer 12

INCREASES adenylate cyclase and also, INCREASES cAMP from ATP.

Question 13

In terms of alpha Gi, what does it do in terms of adenylate cyclase and cAMP?

Answer 13

DECREASES adenylate cyclase and also, DECREASES cAMP from ATP.

Question 14

In terms of alpha Gq//11, what does it do in terms of phospholipase C and DAG // IP3?

Answer 14

INCREASES phospholipase C and also, INCREASES DAG and IP3 levels.
DAG = diacylglycerol
IP3 = Inositol Trisphosphate

Question 15

In terms of MAJOR sympathetic effects, what is the effects of Alpha 1 and Alpha 2 receptors?

Answer 15

Alpha 1 = Vascular smooth muscle contraction.

Alpha 2 = Inhibition of transmitter release.

Question 16

In terms of MAJOR sympathetic effects, what is the effects of Beta 1 and Beta 2 receptors?

Answer 16

Beta 1 = Main cardiac effects.

Beta 2 = Vascular dilation // airway relaxation.

Question 17

What happens in terms of contraction of arterial smooth muscle?

Answer 17

Alpha 1 adrenoreceptor mediated response.

This results in an INCREASE of phospholipase C.

Question 18

Give a brief summary of arterial smooth muscle contraction by noradrenaline.

Answer 18

Alpha 1 activation leads to INCREASED phospholipase C.
Production of IP3 and DAG.
IP3 diffuses into sarcoplasmic reticulum.
INCREASES calcium release.
Thus, DAG has multiple effects.

Question 19

Give a summary of the cardiac effects of noradrenaline due to Beta 1 receptor activation.

Answer 19

B1 activation leads to INCREASED cAMP.
There is MORE stimulation of pacemaker and calcium channels too.
There is also a stimulation of release too.
This all occurs via PROTEIN KINASE A.

Question 20

Give summary of smooth muscle effects of B - stimulation.

Answer 20

INCREASED cAMP
DECREASED Ca release / INCREASED K+ channel activity
DECREASED myosin light chan kinase.
DECREASED contraction.

Question 21

What is the difference between B - adrenoreceptors for cardiac muscle and smooth muscle cells?

Answer 21

Cardiac muscle cells lead to contraction.

Smooth muscle cells lead to relaxation.

Question 22

What are the miscellaneous effects of Alpha adrenoreceptors?

Answer 22

Piloerection = Hair on skin rising.
Seminal vesicle contraction = part of the male urinary system.
Iris muscle contraction = Pupil dilation.

Question 23

What are the miscellaneous effects of Beta adrenoreceptors?

Answer 23

Carbohydrate metabolism.
Influence renin release from kidney.
Lipolysis = glycerol and 3 fatty acids are produced.

Question 24

What is a summary of the physiological effects of the sympathetic nervous system in terms of alpha and beta adrenoreceptors?

Answer 24

Alpha adrenoreceptors :
Alpha 1 = vascular smooth muscle contraction.
Alpha 2 = Inhibition of transmitter release.
Beta adrenoreceptors :
Beta 1 = main cardiac effects.
Beta 2 = vascular dilation // airway relaxation.

Question 25

In terms of muscarinic receptors, which ones have phospholipase C as their enzyme?

Answer 25

M1 = Glands // Secretory Cells 
M3 = Endothelial Cells // Visceral smooth muscle / GI secretions. 
M5 = CNS

Question 26

In terms of muscarinic receptors, which ones have adenylate cyclase as their enzyme?

Answer 26

M2 = Heart  
M4 = CNS

Question 27

In terms of the main parasympathetic effects involved?

Answer 27

Cardiac and Vascular systems.
Secretory cells.
Eye.

Question 28

What are the cardiac effects of acetylcholine due to M2 receptor activation?

Answer 28

Leads to DECREASED cAMP.
Less stimulation of pacemaker // calcium channels // release.
Opens a potassium channel

Question 29

In terms of muscle cells, what is the difference between non - vascular and vascular muscle?

Answer 29

Non - vascular = Contraction

Vascular = Relaxation

Question 30

How do you work out the blood pressure?

Answer 30

Blood pressure = cardiac output x peripheral resistance.

Question 31

Which receptor contracts non - vascular smooth muscle?

Answer 31

M3 receptor.
This activates the M3 receptors in the GI tract // bladder // airways // uterus.
There is an increased activation of phospholipase C and this calcium is also RELEASED.

Question 32

What effect does M3 receptors have on secretory cells?

Answer 32

Affects the salivary glands and the sweat glands.

Question 33

How are the eye muscles in the eye affected by M3 receptors?

Answer 33

In the parasympathetic system = MIOSIS occurs and this is the contraction of the circular muscle.
In the sympathetic system = MYDRIASIS occurs and this is the alpha 1 contraction of the radial muscle.

Question 34

What happens to the eye when M3 receptors are activated?

Answer 34

Contraction of ciliary muscle.
Relaxes suspensory ligaments.
Allows lens to bulge.