Introduction to the ANS

Question 1

What does the somatic nervous system control?

Answer 1

Skeletal muscle (including diaphragm and respiratory muscle)

Question 2

What does the autonomic nervous system control?

Answer 2

Smooth, and cardiac muscle, exocrine glands, metabolism, host defence=

Question 3

What does the neuroendocrine system control?

Answer 3

Growth, metabolism, reproduction, development, salt & water defence

Question 4

Which part of the ANS controls pupil dilation and constriction?

Answer 4

Dilation - Sympathetic NS

Constriction - Parasympathetic NS

Question 5

Which nerve innervates the stomach that controls digestion?

Answer 5

Vagus

Question 6

Describes the effects baroreceptors have when stimulated?

Answer 6

Stimulatory effect on parasympathetic nerves which activate an inhibitory nerve to the heart - decreases HR
Inhibitory effect on the sympathetic nerves - sympathetic stimulation increases HR, it has an effect on the heart and the arterioles and veins.
The arterioles and veins are controlled by sympathetic nerves NEVER by parasympathetic. Arterioles; Constriction and dilation

Question 7

What is the BP proportional to?

Answer 7

Baroreceptor firing rate

Question 8

What NS dominates the heart?

Answer 8

Parasympathetic

Question 9

Draw the diagram for the control of HR with the nerves.

Answer 9

See diagram

Question 10

See diagram with principle target and functions of the ANS

Answer 10

See diagram

Question 11

What controls the ciliary muscle?

Answer 11

Parasympathetic NS

Question 12

What nerves supply the trachea and bronchioles?

Answer 12

Parasympathetic nerves, no sympathetic. There are still sympathetic effects cause Adrenaline is delivered to the lungs.

Question 13

What effect does parasympathetic innervation have on the lungs?

Answer 13

Constriction

Question 14

What nerves supply blood vessels and what do they do?

Answer 14

Sympathetic - dilate and constrict

Question 15

Draw a diagram for the neurotransmitters and receptors in the ANS

Answer 15

See diagram - need to know which neurotransmitter is released from which nerve in the PNS and the SNS as well as receptors

Question 16

How can the PNS be described as?

Answer 16

Discrete and localised - 1:1 pre vs post ganglionic neurone

Question 17

How can the SNS be described as?

Answer 17

Coordinated response and divergent - 1:20 pre vs post ganglionic neurone

Question 18

Where does the PNS and SNS originate from?

Answer 18

PNS: cranial + sacral
SNS: Thoracic + lumbar

Question 19

Where does sensory information of the gut go to?

Answer 19

Information is relayed to submucosal and myenteric plexus via interneurones

Question 20

What are the receptors are the targets for ACh?

Answer 20

Nicotinic and Muscarinic receptors

Question 21

Describe the Nicotinic receptor

Answer 21

1) Found in all autonomic ganglia - they transfer stimulus from the preganglionic to the post ganglionic neurone
2) Type 1 - iontropic. They are ion channel linked
3) FAST
4) Activated by ACh/nicotine and blocked by hexamethonium and trimetaphan

Question 22

Describe the Muscarinic receptor

Answer 22

1) Found on all target organs innervated by post ganglionic parasympathetic nerves
2) Type 2 - G-protein coupled
3) Slower than nicotinic
4) Activated by ACh/Muscarine and blocked by atropine and hyoscine

Question 23

What one exception has muscarinic receptors?

Answer 23

Sweat glands - sympathetic innervation but releases ACh so activates muscarinic receptors on sweat glands

Question 24

Where can muscarinic receptors be found?

Answer 24

Found on any target organ where the post ganglionic neurone releases ACh

Question 25

Which ANS tends to increase urinary frequency?

Answer 25

Parasympathetic (rest and digest)

Question 26

What effect would blockage of nicotinic ACh receptors have on heart rate at rest and during exercise?

Answer 26

Rest: HR increases Exercise: HR lower than expected This question requires you to think about which effect is dominant when. Important

Question 27

What are the sub-types of Muscarinic receptors?

Answer 27

``` M1 - Neural M2 - Cardiac M3 - Exocrine and Smooth muscle M4 - Periphery M5 - Striatal dopamine release ```

Question 28

What are the sub-types of Adrenoreceptors?

Answer 28

a1 a2 b1 b2

Question 29

Describe the adrenoreceptors

Answer 29

1) These receptors are found on the end of the sympathetic nervous system 2) There are 4 subtypes 3) G-protein coupled 4) Stimulated by NA and by A produced by the adrenal medulla

Question 30

What blocks nictoinic receptors?

Answer 30

Hexamethonium

Question 31

What blocks muscarinic receptors?

Answer 31

Atropine

Question 32

What NS controls the vascular system?

Answer 32

SNS a1 - constricts b2 - dilates

Question 33

Describe the synthesis, release and metabolism of ACh

Answer 33

See diagram - all reactants, products and enzymes must be known

Question 34

Describe the synthesis, release, reuptake and metabolism or noradrenaline

Answer 34

See diagram - all reactants, products and enzymes must be known

Question 35

What receptors does NA bind to?

Answer 35

Adrenoreceptors