Autonomic Nervous System

Question 1

What is the central point of integration of the ANS?

Answer 1

Hypothalamus

Question 2

Control via baroreceptors is processed in which part of the brain?

Answer 2

Medulla

Question 3

Describe the parasympathetic nervous system.

Answer 3

PNS is made up of pre- and post- ganglionic fibres arising from two locations:

1. Cranial nerves 3, 7, 9, 10 - supply eye, salivary glands, heart, bronchi, upper GI tract
2. Sacral fibres S2, 3, 4 - supply distal bowel, genitals and bladder.

Post ganglionic fibres release acetylcholine, acting via nicotinic receptors.

Medications such as anticholinergic/ anticholinesterases effect PNS.

Question 4

Sympathetic nervous system arises from where?

Answer 4

Pre-ganglionic fibres arise from the lateral horn of the spinal cords.

Thoracic - Lumbar: T1 - L2

Pass into anterior rami, via white rami communications to the sympathetic chain/ ganglia. Synapse at this level

Or pass anteriorly through a splanchnic nerve.

Question 5

What neurotransmitters act at SNS?

Answer 5

Noradrenaline via the adrenoreceptors.

Question 6

What receptors do sympathomimetics act at?

How do direct and indirectly acting sympathomimetics differ?

Answer 6

Exert effects via adrenoreceptors or dopamine receptors.

Direct attach to receptors.

Indirect - cause release of neurotransmitters to produce effects at these receptors.