Introduction to the ANS

Question 1

5 functions of the ANS

Answer 1

Exocrine glands
SM
Cardiac muscle
Metabolism
Host defence

Question 2

Do most targets in the body receive both PSN and SN innervation?

Answer 2

NO - some targets only receive ONE e.g. blood vessels and SN

Question 3

Pupils response in a dark room?

Answer 3

Pupils dilate
Oculomotor nerve (CNIII) and ciliary ganglion
SN

Question 4

Pupils response in bright light?

Answer 4

Pupils constrict

PSN

Question 5

Stomach response to smell of food?

Answer 5

Rest and digest

PSN (CNX)

Question 6

Basal heart rate?

Answer 6

PSN is dominant at rest

Increase in HR to increase BP (baroreceptors fire less and BP is falling)
SN as baroreceptors NOT inhibiting nerve

Question 7

How are the lungs unique in the ANS?

Answer 7

dilation is under endocrine control

Question 8

PSN?

Answer 8

Long pre-ganglionic
Short post-ganglionic
Cranial/Sacral
ALWAYS Ach

Question 9

SN?

Answer 9

Short pre-ganglionic (Ach)
Long post-ganglionic (NA)
Thoracic/Lumbar
90% on time is the above!

Question 10

What is different about the SN in terms of NTs?

Answer 10

Normally the post-ganglionic NT is always NA (and A) BUT some have Ach such as to the sweat glands

Question 11

What is unique about the enteric NS?

Answer 11

Also under LOCAL control from the gut so does not need to contact the brain all the time

Question 12

How does the Somatic NS work?

Answer 12

Just one ganglia straight to the effector organ which releases Ach

Question 13

2 types of receptors for Ach?

Answer 13

Muscarinic and Nicotinic

Question 14

Nicotinic receptors?

Answer 14

Type 1 (ionotropic)
Nicotine/Ach
Found at ALL ANS pre-ganglia

Question 15

Muscarinic receptors?

Answer 15

Type 2 (G-protein coupled)
Muscarine/Ach
At ALL PSN effector organs (also at the sweat gland for SN)

Question 16

Other name for adrenaline and noradernaline?

Answer 16

Epinephrine and norepinephrine

Question 17

WHAT HAPPENS IN YOU MANIPULATE NICOTINIC RECEPTORS?

Answer 17

Affect the WHOLE ANS as ALL pre-ganglia have nicotinic receptors

Question 18

Which of the following effects would be observed after blockade
of nicotinic acetylcholine receptors in an individual at rest?
x Bronchoconstriction
x Increased sweat production
x Constipation
x Increased urinary frequency
x Short-sightedness

Answer 18

Constipation (OneNote!)

Question 19

What effect would blockade of nicotinic acetylcholine
receptors have on heart rate;

x At rest
x During exercise

Answer 19

OneNote!!

Question 20

Adrenoceptors?

Answer 20

Type 2 - GPC
At effector organs in the SN
Stimulated by NA/A

Question 21

3 things to question about drugs?

Answer 21

1. What is the drug target?
2. Where is the drug target?
3. What is the end result of the interaction?
   (OneNote for examples!)

Question 22

Synthesis and removal of Ach?

Enzymes and substrates!!

Answer 22

1. Acetyl CoA + Choline (catalysed by choline acetyl transferase)
2. Gives Ach and CoA
3. Ach in vesicles…..
4. Broken down by acetylcholinesterase in the synaptic cleft
5. Into choline + acetate
   (OneNote!)

Question 23

Synthesis of NA?

Enzymes and substrates!!

Answer 23

1. Tyrosine to DOPA via. tyrosine hydroxlyase
2. DOPA to Dopamine via. DOPA decarboxylase
3. Dopamine moves into a vesicle
4. Converted to NA via. Dopamine beta-hydroxlase
5. NA released into cleft

Question 24

Removal of NA?

Answer 24

NO enzyme in cleft so via. uptake proteins
1. Uptake protein 1 - monoamine oxidase A (MAO-A)
Releases metabolites
2. Uptake protein 2 - COMT
Degrades it completely down

Question 25

Synthesis of A?

Answer 25

From NA via. PNMT in the adrenal medulla

Question 26

Blockade of which of the following targets would cause the most significant rise in synaptic noradrenaline concentrations?
x Tyrosine hydroxylase
x DOPA decarboxylase
x Uptake 1 transport protein
x Monoamine oxidase
x Cathecol-O-methyl transferase

Answer 26

3 - DIRECT

4,5 - INDIRECT