CVS S4 - The CVS & The Autonomic Nervous System

Question 0

Describe preganglionic neurones in the sympathetic nervous system

Answer 0

Have their cell bodies in the CNS
Cholinergic
Nerve fibres are short
Arise from segments T1-L2 or L3

Question 1

Describe pre-ganglionic neurones in the parasympathetic nervous system

Answer 1

Have their cell bodies in the CNS
Cholinergic
Nerve fibres are long

Question 3

Describe post-ganglionic neurones in the parasympathetic nervous system

Answer 3

Have their cell bodies in the PNS
Noradrenergic (α and β classes, types 1 and 2)
EXCEPTION perspiration and ejaculation pathways cholinergic
Short nerve fibres

Question 4

Describe post-ganglionic neurones in the sympathetic nervous system

Answer 4

Have their cell bodies in the PNS
Cholinergic receptors
Specifically muscarinic receptors and GPCRs
Nerve fibres are long

Question 5

Give examples of effectors of the autonomic nervous system

Answer 5

Smooth muscle
Viscera
Secretory glands

Question 6

Describe the sympathetic nervous system

Answer 6

Thoraco-lumbar outflow
Nerve fibres have cell bodies in all 12 thoracic sections and the first two lumbar sections
Pre-ganglionic neurones have short nerve fibres and are cholinergic
Post-ganglionic neurones have long nerve fibre and are noradrenergic EXCEPT the perspiration ejaculation pathways which are cholinergic

Question 7

Describe the locations of synapses in the parasympathetic nervous system

Answer 7

Usually synapse close to target tissue

Question 8

Describe the location of synapses in the sympathetic nervous system

Answer 8

Most synapse with post-ganglionic neurones at the para vertebral chain of ganglia
Some synapse in a number of prevertebral ganglia: coeliac, superior and inferior mesenteric ganglia

Question 10

Describe the parasympathetic nervous system

Answer 10

Cranio-sacral outflow
Pre-ganglionic neurones have long nerve fibres and are cholinergic (nicotinic)
Post-ganglionic neurones have short nerve fibre and are cholinergic (muscarinic or GPCR)

Question 11

Give the effect and the receptor of sympathetic stimulation to the heart

Answer 11

Sympathetic:
Receptor is β1
Effect is to increase the force of rate of contraction
Parasympathetic:
Receptor is M2
Effect is to decrease the rate of contraction

Question 12

Give the effect and the receptor of parasympathetic stimulation to the heart

Answer 12

Receptor is M2

Effect is to decrease the rate of contraction

Question 13

Give the effect and the receptor of sympathetic stimulation to the airways

Answer 13

Receptor is β2

Effect is to relax the airways

Question 14

Give the effect and the receptor of parasympathetic stimulation to the airways

Answer 14

Receptor is α1

Effect is to contract the airways

Question 15

Give the effect and the receptor of sympathetic stimulation to the pupils

Answer 15

Receptor is α1

Effect is to dilate the pupils

Question 16

Give the effect and the receptor of parasympathetic stimulation to the pupils

Answer 16

Receptor is M3

Effect is to contract the pupils

Question 17

Which type of GPCR stimulates adenylyl cyclase?

Answer 17

The s type: Gs

Question 18

Which type of GPCR inhibits adenylyl cyclase?

Answer 18

The i type: Gi

Question 19

Which type of GPCR stimulates phospholipase C?

Answer 19

The q type: Gq

Question 20

Which type of GPCR stimulates cyclic GMP?

Answer 20

The t type: Gt

Question 21

Which receptors cause the stimulation of adenylyl cyclase?

Answer 21

β1 and β2

Question 22

Which receptors cause the inhibition of adenylyl cyclase?

Answer 22

α2 and M2

Question 23

Which receptors cause the stimulation of phospholipase C?

Answer 23

α1, M1 and M3

Question 24

Describe how the sympathetic nervous system innervates vasculature

Answer 24

Sympathetic NS innervates the smooth muscle of arteries, arterioles and veins
Stimulation causes vasoconstriction via α1 receptors
EXCEPT in specialised vessels eg erectile tissue

Question 25

What is the effect of sympathetic stimulation on vasculature?

Answer 25

Stimulation causes vasoconstriction via α1 receptors

EXCEPT in specialised vessels eg erectile tissue

Question 26

How is vasomotor tone controlled?

Answer 26

By the balance between sympathetic stimulation and vasodilator substances This in turn controls flow around the cvs

Question 27

How variable is vasomotor tone?

Answer 27

It varies between organs and can be changed quickly

Question 28

Describe how vasomotor tone in the skin changes

Answer 28

Skin usually has very high vasomotor tone but for thermoregulation, tone can be reduced

Question 29

Describe how vasomotor tone in skeletal muscle changes

Answer 29

At rest, skeletal muscle has high vasomotor tone but during exercise, this is antagonised by vasodilator metabolites

Question 30

Describe how vasomotor tone in the gut changes

Answer 30

Before a meal, the gut has high vasomotor tone but after eating, various vasodilators are produced in the gut to antagonise sympathetic stimulation

Question 31

What afferent information is used by the medulla oblongata to control heart rate?

Answer 31

Information from baroreceptors in the carotid sinuses and arch of the aorta

Question 32

How does the medulla oblongata control heart rate?

Answer 32

Balance of sympathetic and parasympathetic stimulation to the SAN and AVN Parasympathetic slows and sympathetic speeds Parasympathetic is dominant at rest so initial increases in heart rate are due to a reduction in parasympathetic stimulation, then sympathetic stimulation will take effect too

Question 33

Give the effect and the receptor of sympathetic stimulation to the sweat glands

Answer 33

The effect for the α1 receptor is generalised secretion | The effect for the M3 receptor is localised secretion

Question 34

Give the effect and the receptor of parasympathetic stimulation to the sweat glands

Answer 34

There is no effect and there are no receptors