Autonomic System

Question 1

What two divisions are there in the autonomic nervous system?

Answer 1

• sympathetic

- parasympathetic

Question 2

What does the sympathetic division do?

Answer 2

Produces the responses seen in fright, fight or flight

Question 3

What does the parasympathetic do?

Answer 3

Produces the changes in the resting, recovering or restorative state

Question 4

What effects are seen in the sympathetic response?

Answer 4

• pupils dilate
• heart rate and force increases
• vasodilation
• decreased gut motility and secretion
• saliva secretion reduced

Question 5

What effects does the parasympathetic division have?

Answer 5

-pupils constrict
-gut motility and constriction increases
-saliva secretion increases
(-vessels not connected)
-decreased heart rate

Question 6

What controls most visceral organs?

Answer 6

Both the parasympathetic and the sympathetic

Question 7

What is craniosacral?

Answer 7

Brainstem and sacral spinal cord

Question 8

What is thoracolumbar?

Answer 8

Thoracic and lumbar segments 1-3

Question 9

How are ANS effectors regulated?

Answer 9

Neurons of the CNS regulate the effectors of the ANS through autonomic ganglia neurons

Question 10

Which division of the ANS regulates cardiac output in the short term?

Answer 10

Sympathetic

Question 11

What is the major structural difference between the parasympathetic and the sympathetic?

Answer 11

• the parasympathetic preganglionic fibres are long (from the CNS) whereas the sympathetic are shorter
• the parasympathetic postganglionic fibres are short (to the target) whereas sympathetic are short

Question 12

What is the neurotransmitter at all autonomic ganglia?

Answer 12

Acetylcholine

Question 13

What transmitter do parasympathetic postganglionic fibres release?

Answer 13

Acetylcholine

Question 14

What transmitter do most sympathetic postganglionic fibres release?

Answer 14

Noradrenaline

Question 15

What exceptions are there for sympathetic postganglionic fibre transmitters?

Answer 15

Acetylcholine: sweat glands, skeletal muscle blood vessels
NO: erectile tissue
Postulated: substance P, serotonin, ATP plus others

Question 16

What do acetylcholine receptors also respond to?

Answer 16

Administered doses of nicotine and muscarine

Question 17

What receptors does the heart have for the sympathetic system?

Answer 17

Has beta-1 receptors to respond to noradrenaline to increase rate and force of contraction

Question 18

What does the parasympathetic system act on on the heart?

Answer 18

Acetylcholine acts on pacemaker (sino atrial node) and slows the inherent rhythm
(vagal tone)

Question 19

What chronotropic changes does the ANS have on the heart?

Answer 19

sympathetic = weak, positive
parasympathetic = strong, negative

Question 20

What inotropic changes does the ANS have on the heart?

Answer 20

sympathetic = strong, positive
parasympathetic = weak, negative

Question 21

What does the sympathetic division do to blood vessels?

Answer 21

alpha receptors on most organs mediate constriction

Question 22

Do blood vessels have a parasympathetic supply?

Answer 22

No, other than erectile tissue

Question 23

What does the sympathetic do to the lungs?

Answer 23

Beta-2 receptors mediate dilation of the airways

Question 24

What does the parasympathetic do to the lungs?

Answer 24

bronchioles constrict

Question 25

What does salbutamol do to the lungs?

Answer 25

Selectively dilates bronchioles by activating beta-2 receptors

Question 26

Why does salbutamol not affect the heart?

Answer 26

Heart has mainly beta-1 receptors

Question 27

What effect does sympathetic have on the adrenal medulla?

Answer 27

Preganglionic fibre from CNS release acetylcholine which stimulates the release of adrenaline and noradrenaline into the blood to back up the sympathetic response

Question 28

What effect does the parasympathetic have on the adrenal medulla?

Answer 28

None

Question 29

What is hexamethonium?

Answer 29

An autonomic ganglion-blocking agent

Question 30

What does hexamethonium do?

Answer 30

• removes sympathetic tone
• abolishes parasympathetic response
• parlous state