ANS

Question 1

What are the effector organs of the ANS?

Answer 1

visceral organs, smooth muscle, secretory glands and cardiac muscle.

Question 2

What is the main aim of the ANS?

Answer 2

To maintain homeostasis; a constant internal environment.
Regulate the continuous outputs of the 2 opposing systems, non-stop.
Promotes excretory mechanisms

Question 3

Where does sympathetic fibres come out of the CNS?

Answer 3

T1 to L2

Question 4

Where does parasympathetic fibres come out of the CNS?

Answer 4

Cranial nerve nuclei and S2-4.

CN III, VII, IX and X

Question 5

Where are parasympathetic pre-ganglionic neurons found?

Answer 5

pre-ganglionic neurons in dorsal vagal motor nucleus or spinal segmental nerves of S2-S4 segments.

Question 6

What routes can sympathetic pre-ganglionics take?

Answer 6

synapse in chain at level of origin, synapse at different level to origin up or down the chain or may not synapse in paravertebral chain e.g. splachnic nerves.

Question 7

What are grey and white rami communicantes

Answer 7

Two little connecting tubes for sympathetic fibres to enter ganglionic chain and synapse

Question 8

What are the two variants of sympathetic outflow targets?

Answer 8

Somatic targets: travel along segmental nerves
Visceral targets: largely supplued vua pre-ganglionated trunks known as splachnic nerves. Terminate on pre-vertebral ganglia. Supply abdominal viscera via coeliac, superior and inferior mesenteric ganglia

Question 9

How do sympathetic post-ganglionic fibres reach the head and neck?

Answer 9

By hitch hiking on arterial system of head and neck via common carotids, external and internal. Lie outside carotid sheath.