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Flashcards in Sympathetic nervous system Deck (24)
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1
Q

Where do preganglionic sympathetic axons terminate? (3)

A
  1. Paravertebral sympathetic chains
  2. Prevertebral ganglia/plexuses - abdominal cavity: coeliac, superior mesenteric and hypogastric
  3. Adrenal medulla - 10th & 11th segment
2
Q

Describe the sympathetic ganglionic structure:

A

Preganglionic fibres are SHORT, post ganglionic fibres are LONG

3
Q

What is the receptor and neurotransmitter on the sympathetic prevertebral ganglion? (same as PS NS)

A

Receptor: Nicotinic
Neurotransmitter: ACh

4
Q

Where is the preganglionic nerve located?

A

Thoraco-lumbar spinal cord

5
Q

What is the most common receptor and neurotransmitter on the postganglionic axon to effector?

A

Receptor: Adrenoreceptors
Neurotransmitter: Noradrenaline

6
Q

What releases noradrenaline?

A

Varicosities

7
Q

What are the steps in noradrenaline synthesis and use? (6)

A
  1. Tyrosine
  2. NA synthesis (enzymes)
  3. MAO is released (monoamine oxidase)
  4. NA is packaged into vesicles
  5. Varicosities are evaded
  6. Released by exocytosis
8
Q

What are the receptors on the post synaptic cell?

A

Alpha and Beta adrenoreceptors

9
Q

What receptor causes inhibition of NA on presynaptic cell and how does it work?

A

Alpha 2 receptors act as a brake, recycling the NA to be reused

10
Q

What are the uptakes on post and presynaptic cleft for?

A

They reduce levels in the synaptic cleft which stops perpetual activation

11
Q

What type of receptors are a and b adrenoreceptors?

A

Metabotrophic receptors

12
Q

What does a metabotrophic receptor do? (4)

A
  1. Attaches to a G protein
  2. Activates a 2nd messenger system
  3. Enzyme activation/ion transport
  4. Response (change in shape)
13
Q

What receptors can be found on the post synaptic cleft?

A

a1, a2, b1, b2, b3

14
Q

What receptors can be found on the pre synaptic cleft?

A

ONLY a2

15
Q

What receptors are AGONISTS and what can they be used for? (3)

A
  1. a1 - decongestant, eye drops, mydriasis (constrict blood vessels)
  2. b2 - salbutamol (asthma inhaler) relaxes airways
  3. b1 - enhance cardiac muscle contraction
16
Q

What receptors are ANTAGONISTS and what can they be used for? (2)

A

a1 - antihypertensive

b - beta blockers, can slow HR

17
Q

At a synapse, how would a AGONISTIC a2 receptor affect NA?

A

Would reduce NA release as it would uptake more to the presynaptic cell

18
Q

At a synapse, how would a ANTAGONISTIC a2 receptor affect NA?

A

Would increase NA release as it would lower the uptake

19
Q

How does SNS control pupil diameter? (3)

A
  1. Sympathetic nerve activation
  2. Radial muscle contraction (ciliary) or relaxing
  3. Pupil dilation or pupil decreases in size
20
Q

What receptor is used at the eye?

A

Muscarinic 3 (M3)

21
Q

What can mydriatic drugs be used for?

A

Eye inspection and surgery - dilation

22
Q

What can anti glaucoma drugs be used for?

A

Miosis, pupil constricts and releases pressure

23
Q

What is neuropeptide Y and what does it do? (3)

A

Nueromodulator that:

  1. Prejunctional - decreases NA & ATP release
  2. Post junctional - increases NA action
  3. Acts with ATP for VASCONSTRICTION
24
Q

What is adenosine 5’-triphosphate and what does it do? (3)

A

ATP

  1. Directs actions - P2 receptors
  2. Neuromodulator - P1 receptors
  3. Acts with NPY for VASOCONSTRICTION