4 CVS

Question 1

What define parasympathetic and sympathetic systems?

Answer 1

The origin of the presynaptic nerve.

• cranial and sacral: parasympathetic
• thoracic and lumbar: sympathetic

Question 2

sympathetic activity in increased when…

Answer 2

stressed

Question 3

The effect of the sympathetic system on the pupil of the eye is…

Answer 3

dilation (if fighting need to see really well)

Question 4

Which receptor mediates the effect of the sympathetic system on the pupil?

Answer 4

a1 adrenoceptor

Question 5

What effect does the parasympathetic system have on the pupil of the eye?

Answer 5

cintraction

Question 6

Which receptor mediates the effect of the parasympathetic system on the pupil?

Answer 6

M3 muscarinic

Question 7

Contraction of which muscle is responsible for pupil dilation?

Answer 7

radial muscle contraction

Question 8

Contraction of which muscle is responsible for pupil contraction?

Answer 8

sphincter muscle contraction

Question 9

Which receptors mediate the effect of the sympathetic system on the lungs?

Answer 9

b2 adrenoceptors

Question 10

Which receptors mediate the effect of the parasympathetic system on the lungs?

Answer 10

M3 muscarinic receptors

Question 11

which receptors mediate the effect of the sympathetic system on the heart?

Answer 11

b1 adrenoceptors

Question 12

which receptor mediates the effect of the parasympathetic the heart?

Answer 12

M2 muscarinic

Question 13

Which receptors mediate the effect of the symapthetic system on the sweat glands?
in the case of localised secretion (eg. palms)?

Answer 13

a1 adrenoceptors

Question 14

Which receptors mediate the effect of the symapthetic system on the sweat glands in the case of generalosed secretion?

Answer 14

M3 muscarinic

Question 15

What effect does the parasympathetic system have on the sweat glands?

Answer 15

NONE!

Question 16

Is an increase in sympathetic drive generalised to alltissues or are they dissociated?

Answer 16

They are dissociated as far as sympathetic drive is concerned.
eg. sympathetic activity to the heart can be increased without increasing activity to GI tract

Question 17

Ehich 3 main activities does the autonomic nervous system control?

Answer 17

1. smooth muscle (vacular and visceral)
2. Exocrine secretion
3. rate and force of contraction of the heart

Question 18

Does the ANS initiate electrical activity in the heart?

Answer 18

NO, SA node. ells spontaneously depolarise..

a dennervated heqrt still bests. but faster.

Question 19

If ANS effect on heart was cut off what would happen?

Answer 19

the heart would continue to contract but at a faster rate. Why? because at rest the heart is normally under vagal control.

Question 20

What does the ANS exert control over in the heart?

Answer 20

• heart rate
• force of contraction
• and a parasympathetic tone at rest lower the heart beat. ie. if heart was dennervated, it would beat faster at about 100 bpm

Question 21

Where does the vagus nerve synapse with the postganglionic fibers?

Answer 21

On epicardial surface or within the walls of the heart. so the postganglionic nerve is very short.

Question 22

Which parasympathetic pregsnglionic nerve innervates the heart? name and number

Answer 22

10th cranial nerve. called vagus