Lecture 8 - Introuction To The Autonomic Nervous System

Question 1

Divisions of the nervous system

Answer 1

Central nervous system and the peripheral nervous system

Question 2

Main function of the autonomic nervous system

Answer 2

To carry output from the CNS to the whole body, except skeletal muscle

Question 3

What does the ANS regulate

Answer 3

Visceral functions that are largely involuntary, exocrine and certain endocrine functions, the heartbeat and aspects of metabolism

Question 4

Divisions of the ANS

Answer 4

Sympathetic and parasympathetic

Question 5

What does the parasympathetic division coordinate

Answer 5

The body’s basic homeostatic functions

Question 6

What does the sympathetic division coordinate

Answer 6

The body’s response to stress and is associated with flight, fright and fight reactions

Question 7

Travel path of an efferent signal

Answer 7

Travels from the CNS, along preganglionic neurones, to the synapse of the neurone causing neurotransmitter to be released. This is taken up by the associated cell body of the post ganglionic neurone. It travels down the post ganglionic neurone to the effector cell.
CNS -> synapse -> neurotransmitter released -> taken up by Post ganglionic neurone -> travels to effector cell.

Question 8

What is the autonomic ganglion

Answer 8

Where the end of the neurone from the CNS and the start of the neurone of the ANS meet

Question 9

Examples of effector cells

Answer 9

Cardiac cell, smooth muscle cell, secretory cell

Question 10

Functions of the sympathetic system

Answer 10

Constricts many blood vessels but dilates those of skeletal muscles, erects hair, stimulates sweat glands, dilates pupils, dilates bronchi, decreases mucus production, increases heart rate + contractility, slows gut motility, stops secretions of the gut, shut sphincter, stimulates the liver to export fatty acid + glucose, increases renin secretion and causes adrenaline to be released

Question 11

How does the sympathetic system dilate the bronchi

Answer 11

Through the release of adrenaline

Question 12

A decrease in mucus production causes

Answer 12

A decrease in airway resistance

Question 13

Functions of the parasympathetic system

Answer 13

Constricts pupils, stimulates tears, stimulates salivation, constricts bronchi, stimulates mucus secretion, decreases the heart rate, constricts the gall bladder, stimulates pancreatic secretion, increases gut motility + secretions, relaxes sphincters and contracts the bladder

Question 14

What does an increase in mucus production cause

Answer 14

An increase in airway resistance

Question 15

What is the transmitter in the pre ganglionic neurones of the ANS

Answer 15

Acetylcholine

Question 16

Transmitter in the post ganglionic neurone for the sympathetic system

Answer 16

Noradrenaline

Question 17

What type of transmitter is noradrenaline

Answer 17

Adrenergic

Question 18

Transmitter in the post ganglionic neurone for the parasympathetic system

Answer 18

Acetylcholine

Question 19

What type of transmitter is acetylcholine

Answer 19

Cholinergic

Question 20

What does the uptake of a precursor in the synapse cause

Answer 20

The synthesis of a transmitter

Question 21

Where is the transmitter stored

Answer 21

Within vesicles

Question 22

An AP causes what effect on the synapse

Answer 22

It causes the synapse to depolarise

Question 23

Depolarisation of the synapse causes

Answer 23

Ca2+ voltage-gated channels to open so there is an influx of Ca2+

Question 24

What does an influx of Ca2+ into the synapse cause

Answer 24

For the transmitter to be released

Question 25

What is the release of neurotransmitter known as

Answer 25

Exocytosis

Question 26

What does the release of transmitter cause

Answer 26

The activation of the receptors on the post synaptic membrane

Question 27

Once the receptors on the post synaptic membrane are activated what happens

Answer 27

The neurotransmitter is degraded by enzymes or reabsorbed by the synapse

Question 28

What channels does the release of ACh from the preganglionic neurone open

Answer 28

Ligand-gated ion channels

Question 29

What type of receptors are ligand-gated ion channels

Answer 29

Nicotinic ACh receptors

Question 30

Where are nicotinic receptors found

Answer 30

Post ganglionic neurone

Question 31

What does noradrenaline activate

Answer 31

G-protien-coupled adrenoceptors

Question 32

Where does noradrenaline act upon

Answer 32

The target cell

Question 33

What does ACh in the post ganglionic neurone activate

Answer 33

G-protein-coupled muscarinic acetylcholine receptors

Question 34

In cholinergic transmission, what is taken up by the transporter

Answer 34

Choline

Question 35

What does the uptake of choline cause

Answer 35

The synthesis of ACh

Question 36

Through what mechanism is ACh synthesised from choline

Answer 36

Choline acetyltransferase (CAT)

Question 37

What degrades ACh

Answer 37

Acetylcholinesterase

Question 38

ACh causes the activation of what subtypes of ACh muscarinic receptors

Answer 38

M1, M2 and M3

Question 39

In noradrenic transmission what causes the synthesis of noradrenaline

Answer 39

L-tyrosine

Question 40

What are the transporters known as that reabsorb noradrenaline

Answer 40

Uptake 1 (U1) and uptake (U2)

Question 41

What metabolises noradrenaline

Answer 41

Monoamine oxidase (MO) and catecholo-o-methlytransferase (COMT)

Question 42

Associated M1 g-protien

Answer 42

Gq

Question 43

What does the M1-Gq coupling cause

Answer 43

The stimulation of phospholipase C which causes an increase in acid secretion

Question 44

The associated M2 G-protien

Answer 44

Gi

Question 45

What does the M2-Gi coupling cause

Answer 45

Inhibition of adenyly cyclase which opens the K+ channels which causes a decreased heart rate

Question 46

The associated M3 G-protein

Answer 46

Gq

Question 47

What does the M3-Gq coupling cause

Answer 47

The stimulation of phospholipase C which causes an increase in the secretion of saliva and contraction of the bronchi

Question 48

What indirectly effect does M3 receptor activation have

Answer 48

The relaxation of vascular smooth muscle due to the release of nitric oxide from neighbouring cells

Question 49

The two main classes of adrenoceptors

Answer 49

Alpha-adrenoceptors and beta-adrenoceptors

Question 50

Isoforms of alpha-adrenoceptors

Answer 50

Alpha 1 and alpha 2

Question 51

Isoforms of beta-adrenoceptors

Answer 51

Beta 1 and beta 2

Question 52

Beta 1 associated G-protein

Answer 52

Gs

Question 53

What does the beta 1-Gs coupling cause

Answer 53

The stimulation of adenyly cyclase which causes an increase in the rate and force of the heart contractions

Question 54

Beta 2 associated G-protein

Answer 54

Gs

Question 55

What does the beta 2-Gs coupling cause

Answer 55

The stimulation of adenyly cyclase which causes relaxation of the bronchi and vascular smooth muscle

Question 56

Alpha 1 associated G-protein

Answer 56

Gq

Question 57

What does the alpha 1-Gq coupling cause

Answer 57

Stimulation of phospholipase C which causes the constriction of vascular smooth muscle

Question 58

Alpha 2 associated G-protein

Answer 58

Gi

Question 59

What does the alpha 2-Gi coupling cause

Answer 59

The inhibition of adenyly cyclase at pre-junctional terminals which inhibits the release of noradrenaline