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Yr 2 - Pharmacology > ANS > Flashcards

Flashcards in ANS Deck (44):
1

Which neurotransmitter is released at the parasympathetic first synapse?

Acetylcholine

2

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

Nicotinic ACh

3

Which neurotransmitter is released at the parasympathetic second synapse?

Acetylcholine

4

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

Muscarinic ACh

5

Which neurotransmitter is released at the sympathetic first synapse?

Acetylcholine

6

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

Nicotinic ACh

7

Which neurotransmitter is released at the sympathetic second synapse?

Noradrenaline

8

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

Alpha & beta adrenoreceptors

9

Which axon is longest in the parasympathetic nervous system?

Presynaptic (synapses near target organ)

10

Which axon is longest in the sympathetic nervous system?

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

11

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

Sweat glands

Blood vessels

(SYMPATHETIC)

12

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

GIT

Bladder

Salivary glands

13

What is the effect of the parasympathetics on the heart?

Slows

14

What is the effect of the sympathetics on the heart?

Fast

15

Name an organ in which the parasympathetics and sympathetics work together

Salivary glands

16

What are the 3 different types of G proteins?

q

s

i

17

What is a varicosity?

Sites where synapses occur along an axon = bulges out

A image thumb
18

1 in how many presynaptic action potentials cause a release?

50

19

Which types of receptors are located at ganglionic synapses?

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

20

What type of receptors are found at post ganglionic synapses?

Metabotrophic (GPCR) = changes what goes on inside cell

21

What is the action of displacing agents?

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)

22

What is pephedrine used for?

= displacing agent

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

 

23

What is pseudoephedrine used for?

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

= displacing agent

n.b. some sudafeds and lemsips contain phenylephrine instead

24

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

Cause severe hypotension

25

What foods is tyramine found in?

mature cheese

pickled herring

broad bean pods

marmite

 

26

What does tyramine cause?

High blood pressure

Sweating

 

27

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

Hypertensive crysis 

= hypertension, tachycardia (/reflex bradycardia)

28

In which situations is methyldopa the preferred anti-hyertensive?

When other treatments have failed

In pregnancy

29

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

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

30

What does guanethidine do?

Noradrenergic neurone blocking drug

= rapid control of blood pressure in hypertensive emergency (depletes nerve endings of NA = no longer work) 

VERY SEVERE SIDE EFFECTS

31

SYMPATHETICS

Which receptors are the most prevalent in the heart?

Beta 1 adrenoreceptors

(sympathetics)

32

SYMPATHETICS

What is the effect of the SNS on the heart?

Increased rate and contractility

33

SYMPATHETICS

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

Alpha 1 adrenoreceptors

34

SYMPATHETICS

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

They are extrasynaptic

35

SYMPATHETICS

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

Beta 

(n.b. effect it concentration dependant)

36

SYMPATHETICS

With a low circulating adrenaline level which receptors are activated?

And what is their effect?

Beta 2

Vasodilation

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

 

37

SYMPATHETICS

With a high circulating adrenaline level which receptors are activated?

And what is their effect?

Alpha 1

Vasoconstriction

= activates phospholipase C = IP3 = increased intracellular Ca = contraction

38

SYMPATHETICS

What are the main type of receptor in the lungs?

Beta 2 adrenoreceptors

39

SYMPATHETICS

What are the lungs beta 2 adrenoreceptors activated by?

Circulating adrenaline or beta 2 agonists

40

SYMPATHETICS

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

Brochodilation

41

PARASYMPATHETICS

What happens when muscarinic receptors are stimulated?

  • 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)

42

What are the side effects of inhibition of muscarinic receptors?

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

43

Which famous plant causes atrophine poisoning?

Deadly nightshade

44

Why dont we use drugs for nACh receptors?

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