ANS Workshop

Question 1

What are the divisions of the CNS?

Answer 1

• Brain
• Spinal Cord

Question 2

What are the divisions of the peripheral nervous system?

Answer 2

• Somatic Nervous System
• ANS - splits into Sympathetic and Parasympathetic Nervous Systems

Question 3

What are the two types of neurones within the peripheral nervous system?

Answer 3

• AFFERENT (sensory) neurones - bring information to CNS
• EFFERENT (motor) neurones - carry information away from CNS

Question 4

What are the two types of neurones in the peripheral nervous system?

Answer 4

• ALPHA motor neurones - innervate skeletal muscle
• AUTONOMIC neurones - innervate smooth muscle, glands

Question 5

What is an autonomic neural pathway composed of?

Answer 5

• Preganglionic neurone from CNS
• Synapses with postganglionic fibre at autonomic ganglia

Question 6

Describe structure of the sympathetic nervous system.

Answer 6

• Autonomic ganglia close to spinal cord
• Pre-ganglionic neurones originate between T1-L2 on spinal cord
• ACh released from pre-ganglionic fibre and binds nicotinic receptors. Inactivated by AChesterase
• Noradrenaline released from post-ganglionic pre-synaptic terminal and binds adrenergic receptors

Question 7

Describe structure of the parasympathetic nervous system.

Answer 7

• Cell bodies originate in cranial or sacral region
• Ganglia close to or on effector tissue
• Pre-ganglionic fibres are long, release ACh which bind nicotinic receptors.
• Post-ganglionic fibres are short, release ACh which binds muscarinic receptors.

Question 8

What type of receptors are the following?
- ADRENERGIC AND MUSCARINIC
- NICOTINIC

Answer 8

• ADRENERGIC AND MUSCARINIC - GPCRs
• NICOTINIC - Ligand gated ion channel receptors

Question 9

Where are the following receptors found?
- CHOLINERGIC NICOTINIC
- ADRENERGIC α
- CHOLINERGIC MUSCARINIC
- ADRENERGIC β

Answer 9

• Autonomic preganglionic neurone
• Somatic motor neurone
• Parasympathetic post-ganglionic neurone
• Sympathetic post-ganglionic neurone

Question 10

What enzymes do the following adrenoreceptors activate?
- α1
- α2
- β1
- β2
- β3

Answer 10

• α1 ADRENORECEPTOR
  Enzyme: STIMULATE Phospholipase C (Gαq/11)
• α2 ADRENORECEPTOR
  Enzyme: INHIBIT Adenylate Cyclase (Gαi)
• β1/2/3 ADRENORECEPTOR
  Enzyme: STIMULATE Adenylate Cyclase (Gαs)

Question 11

An agonist such as adrenaline at the B1 receptor causes the heart rate to increase. What physiological response would the doctor see if the doctor administered a B1 antagonist such as propranolol to the patient?

Answer 11

Decreased heart rate

Question 12

An antagonist such as propranolol at the B2 receptor causes the heart rate to decrease and constriction of bronchial smooth muscle. What physiological response would the doctor see in the lung if the doctor administered a B2 agonist such as salbutamol to the patient?

Answer 12

Decreased bronchial smooth muscle contraction

Question 13

An agonist such as bethanechol at the M3 receptor causes increased gut motility and increased secretions in the gut. What diagnosis might the patient experience?

Answer 13

Diarrhoea

Question 14

What is the effect of activating the following adrenoreceptors by the sympathetic nervous system:
- α1
- α2
- β1
- β2
- β3

Answer 14

• α1- vasoconstriction
• α2 - inhibits noradrenaline release
• β1 - increased heart rate
• β2 - bronchodilation
• β3 - lipolysis

Question 15

What is the effect of activating the following adrenoreceptors by the parasympathetic nervous system:
- M1
- M2
- M3

Answer 15

• M1 - excitation of ganglia
• M2 - decrease in heart rate
• M3 - vasodilation