ANS

Question 1

Which neurotransmitter is released at the parasympathetic first synapse?

Answer 1

Acetylcholine

Question 2

Which type of receptor accepts the neurotransmitter at the parasympathetic first synapse?

Answer 2

Nicotinic ACh

Question 3

Which neurotransmitter is released at the parasympathetic second synapse?

Answer 3

Acetylcholine

Question 4

Which type of receptor accepts the neurotransmitter at the parasympathetic second synapse?

Answer 4

Muscarinic ACh

Question 5

Which neurotransmitter is released at the sympathetic first synapse?

Answer 5

Acetylcholine

Question 6

Which type of receptor accepts the neurotransmitter at the sympathetic first synapse?

Answer 6

Nicotinic ACh

Question 7

Which neurotransmitter is released at the sympathetic second synapse?

Answer 7

Noradrenaline

Question 8

Which type of receptor accepts the neurotransmitter at the sympathetic second synapse?

Answer 8

Alpha & beta adrenoreceptors

Question 9

Which axon is longest in the parasympathetic nervous system?

Answer 9

Presynaptic (synapses near target organ)

Question 10

Which axon is longest in the sympathetic nervous system?

Answer 10

Postsynaptic (synapses in sympathetic trunk = runs next to spinal cord)

Question 11

Name two target organs purely innervated by only Sympathetic or the parasympathetic nervous system

Answer 11

Sweat glands

Blood vessels

(SYMPATHETIC)

Question 12

Name 3 organs innervated by both the sympathetic and parasympathetic nervous system but the parasympathetic innervation predominates

Answer 12

GIT

Bladder

Salivary glands

Question 13

What is the effect of the parasympathetics on the heart?

Answer 13

Slows

Question 14

What is the effect of the sympathetics on the heart?

Answer 14

Fast

Question 15

Name an organ in which the parasympathetics and sympathetics work together

Answer 15

Salivary glands

Question 16

What are the 3 different types of G proteins?

Answer 16

q

s

i

Question 17

What is a varicosity?

Answer 17

Sites where synapses occur along an axon = bulges out

Question 18

1 in how many presynaptic action potentials cause a release?

Answer 18

50

Question 19

Which types of receptors are located at ganglionic synapses?

Answer 19

Inotrophic (ligand gated ion channels = acivated by 2 ACh = conformational change)

Question 20

What type of receptors are found at post ganglionic synapses?

Answer 20

Metabotrophic (GPCR) = changes what goes on inside cell

Question 21

What is the action of displacing agents?

Answer 21

They displace the NA from the synapse (displaces it from the varicosity)

• competes with NA for uptake 1 (decrease reuptake of NA)
• competes with NA for vesicular transporters
• more NA in varicosity (reverse uptake 1 = Na & NA move out)

Question 22

What is pephedrine used for?

Answer 22

= displacing agent

• reverse hypotension after epidural anaesthesia
• decongestant nasal drops (vasoconstriction of mucosal blood vessels)

Question 23

What is pseudoephedrine used for?

Answer 23

Systemic nasal decongestant (in sprays, sudafed, lemsip & claritin D)

= displacing agent

n.b. some sudafeds and lemsips contain phenylephrine instead

Question 24

What is the action of amfetamine, metamfetamine & ecstacy at the CNS?

Answer 24

Cause severe hypotension

Question 25

What foods is tyramine found in?

Answer 25

mature cheese pickled herring broad bean pods marmite

Question 26

What does tyramine cause?

Answer 26

High blood pressure Sweating

Question 27

What happens when you give a person already taking a drug to increase snaptic [NA] a displacing agent too?

Answer 27

Hypertensive crysis = hypertension, tachycardia (/reflex bradycardia)

Question 28

In which situations is methyldopa the preferred anti-hyertensive?

Answer 28

When other treatments have failed In pregnancy

Question 29

What are the 2 different methods of action for methylopa as an anti-hypertensive?

Answer 29

Alpha 2 adrenoreceptor agonist 1. **inhbits NA exocytosis** (also competes with NA & enters variosity through uptake 1 -\> into vesicles =\> methyldopamine =\> methylNA 2. **reduces sympathetic drive to CNS** -\> crosses BBB = inhibits/reduces firing of SNS = decreased [NA] at synapses

Question 30

What does guanethidine do?

Answer 30

Noradrenergic neurone blocking drug = rapid control of blood pressure in hypertensive emergency (depletes nerve endings of NA = no longer work) VERY SEVERE SIDE EFFECTS

Question 31

SYMPATHETICS Which receptors are the most prevalent in the heart?

Answer 31

Beta 1 adrenoreceptors | (sympathetics)

Question 32

SYMPATHETICS What is the effect of the SNS on the heart?

Answer 32

Increased rate and contractility

Question 33

SYMPATHETICS Which receptors are involved in constant sympathetic tone of the blood vessels?

Answer 33

Alpha 1 adrenoreceptors

Question 34

SYMPATHETICS Why are beta 2 receptors in blood vessels not activated by NA from nerves?

Answer 34

They are extrasynaptic

Question 35

SYMPATHETICS Which type of adrenoreceptors does circulating adrenaline (e.g. from stress) have a greater effect on?

Answer 35

Beta (n.b. effect it concentration dependant)

Question 36

SYMPATHETICS With a low circulating adrenaline level which receptors are activated? And what is their effect?

Answer 36

Beta 2 Vasodilation (activates adenyl cyclase = increase cAMP = inhibits myosin light chaine kinase = less contraction)

Question 37

SYMPATHETICS With a high circulating adrenaline level which receptors are activated? And what is their effect?

Answer 37

Alpha 1 Vasoconstriction = activates phospholipase C = IP3 = increased intracellular Ca = contraction

Question 38

SYMPATHETICS What are the main type of receptor in the lungs?

Answer 38

Beta 2 adrenoreceptors

Question 39

SYMPATHETICS What are the lungs beta 2 adrenoreceptors activated by?

Answer 39

Circulating adrenaline or beta 2 agonists

Question 40

SYMPATHETICS When the lungs beta adrenoreceptors are activated what happens to the lungs?

Answer 40

Brochodilation

Question 41

PARASYMPATHETICS What happens when muscarinic receptors are stimulated?

Answer 41

* Exocrine secretions = increased in salivary glands, GI tract, lacrimal & sweat glands * Smooth muscle = mainly contract (excluding blood vessels) * Heart = mostly inhibitory (hyperpolarisation via Gi) * ACh release from parasympathetic varicosities (inhibits Ca channels) * Vasodilation (NO from endothelial cells)

Question 42

What are the side effects of inhibition of muscarinic receptors?

Answer 42

* Restlessness * Agitation * Disorientation (atropine) * Sedation * Amnesia (hyoscine)

Question 43

Which famous plant causes atrophine poisoning?

Answer 43

Deadly nightshade

Question 44

Why dont we use drugs for nACh receptors?

Answer 44

We wouldn't be able to selectively activate SNS/PNS = mix of effects and would trigger autonomic reflexes