The Autonomic Nervous System

Question 1

Name the two functional divisions of the autonomic nervous system.

Answer 1

Sympathetic

Parasympathetic

Question 2

Name the nervous system which acts on the gut.

Answer 2

The enteric nervous system

Question 3

What is the parasympathetic system important for?

Answer 3

Digestion, excretion, visual accomodation.
‘Rest and digest’
Less widespread innervation and effects.

Question 4

What is the sympathetic system important for?

Answer 4

Ongoing control of the cardiovascular system.
‘Fight, flight, fright’
More widespread innervation and effect.

Question 5

Which branch of the autonomic nervous system has more widespread innervation and effect?

Answer 5

The sympathetic system.

Question 6

Which spinal nerve roots do the sympathetic nerves arise from?

Answer 6

T1 to L2

Question 7

Which spinal nerve roots do the parasympathetic nerves arise from?

Answer 7

Cranial nerves III, VII, IX, X

S2-S4

Question 8

How many neurons make up an autonmic nerve track?

Answer 8

Always 2.

Synapse in ganglia (except in adrenal medulla)

Question 9

Where do parasympathetic neurons in series synapse?

Answer 9

Ganglia in the tissue of effector.

Question 10

Where do sympathetic neurons synapse?

Answer 10

In sympathetic chain ganglia OR at adrenal medulla (not in ganglion)

Question 11

What neurotransmitter is released at parasympathetic synapse?

Answer 11

Acetylcholine

Question 12

What sort of receptor is present in the post-synaptic neuron in parasympathetic ganglia?

Answer 12

Nicotinic receptor.

Question 13

What sorts of receptor do acetyl choline bind to?

Answer 13

Nicotinic receptorat ganglia.

Muscarinic receptor at effector.

Question 14

What neurotransmitter does a parasympathetic post-ganglionic neurone release?

Answer 14

Acetylcholine

Question 15

What sort of receptor is found on parasympathetic effectors?

Answer 15

Muscarinic

Question 16

Outline a parasympathetic efferent pathway.

Answer 16

Pre-ganglionic neuron releases acetylcholine at synapse in ganglia.
Acetylcholine binds to nicotinic receptors on post-ganglionic neuron.
Post-ganglionic neuron releases acetylcholine at neuro-effector junction.
Acetylcholine binds to muscarinic receptors on effector cell surface.

Question 17

What sort of receptor does noradrenaline bind to?

Answer 17

Adrenergic receptors

alpha, beta

Question 18

What neurotransmitter is released at all sympathetic synpases?

Answer 18

Acetylcholine

Question 19

In most sympathetic pathways what neurotransmitter is released by the post-ganglionic neuron?

Answer 19

Noradrenaline

Question 20

In sweat gland innervation, what neurotransmitter is released by the post-ganglionic neuron?

Answer 20

Acetylcholine

(very similiar to parasympathetic nerve pathway but ganglia occur in sympathetic chain)

Question 21

What receptors are present on sweat glands?

Answer 21

Muscarinic receptors

Question 22

What receptors are present on the adrenal medulla?

Answer 22

Nicotinic receptor

Question 23

What neurotransmitter(s) do the adrenal medulla release?

Answer 23

Noradrenaline and adrenaline (bind to adrenergic receptors)

Question 24

What are the two types of cholinergic receptors?

Answer 24

Nicotinic and muscarinic

Question 25

Which type of cholinergic receptor is G-coupled?

Answer 25

Muscarinic

Question 26

Where are M2 isoform muscarinic receptors found?

Answer 26

In the heart, regulate cardiac function. | Parasympathetic (slow heart rate)

Question 27

Where are M3 isoform muscarinic receptors found?

Answer 27

In smooth muscle and glands act through Gproteins. | Activates phospholipase C - produces IP3 and DAG.

Question 28

What are the types of adrenergic receptor?

Answer 28

α (1 and 2) | β ( 1, 2, 3)

Question 29

What is the function of α1 receptors?

Answer 29

Activates Gq - stimulates IP3/Ca2+ and DAG. | Raises cellular calcium concentration

Question 30

What is the function of α2 receptors?

Answer 30

Activates Gi - inhibits adenylate cyclase. | Reduces cAMP prodcution.

Question 31

What is the function of all β receptors?

Answer 31

Activate Gs - increase concentration of cAMP.

Question 32

Where are each β receptors found?

Answer 32

``` β1 = cardiac subtype β2 = vascular and airways subtype β3 = adipose tissue and bladder ```

Question 33

What neurotransmitter do adrenergic receptors respond to?

Answer 33

Noradrenaline and adrenaline

Question 34

What is non-adrenergic, non-cholinergic neurotransmission?

Answer 34

Neurotransmission that does not involve acetylcholine or noradrenaline. May result in co-transmission of neurotransmitter. Important in CNS and enteric nervous system.

Question 35

Give some sympathetic effects on the body.

Answer 35

Increased heart rate and force of contraction. Bronchodilation Vasoconstriction (but dilation of arteries in heart) Bladder relaxation Decrease GI motility

Question 36

Give some parasympathetic effects on the body.

Answer 36

Decreased heart rate Increased gastrointestinal and other secretions Bronchoconstriction Micturition - contraction of detrusor muscles Defaecation

Question 37

Outline the baroreceptor reflex. (4 steps)

Answer 37

1. Blood pressure increase distends arterial walls (activates stretch receptors) 2. Stretch receptors signal to brain stem which compares blood pressure to set point. 3. Increased parasympathetic stimulation to the heart - slows heart rate. 4. Decreased sympathetic drive to the heart

Question 38

What is the reaction that produce acetylcholine and what enzyme catalyses this reaction?

Answer 38

Acetyl-CoA + Choline > Acetylcholine | Catalyses by choline acetyltransferase

Question 39

What enzyme breaks down acetylcholine?

Answer 39

Acetylcholinesterase

Question 40

What is the enteric nervous system?

Answer 40

Brain of the gut, forms 2 layers of motor, sensory and interneurons in the wallls of the GI tract.

Question 41

What are the two layers of the enteric nervous system?

Answer 41

Myenteric plexus | Submucosal plexus

Question 42

What does the ENS co-ordinate?

Answer 42

Peristalsis, fluid transport, glandular secretions and blood flow within the GI tract.