Nervous Control Of The Gut

Question 1

What is released by all preganglionic fibres?

Answer 1

Acetylcholine

Question 2

What is released by post ganglionic fibres?

Answer 2

Sympathetic: noradrenaline mainly, some ACh
Parasympathetic: acetylcholine

Question 3

Outline the sympathetic pre and post ganglionic fibres

Answer 3

• short myelinated pre-ganglionic > ACh
• long non-myelinated post ganglionic > NA (some ACh)

Question 4

Outline the parasympathetic pre and post ganglionic fibres

Answer 4

• long myelinated pre ganglionic > ACh
• short non-myelinated post ganglionic > ACh

Question 5

Outline the parasympathetic nervous system innervation on the gut

Answer 5

• rest and digest
• cranio-sacral outflow: vagus nerve + pelvic splanchnic nerves (S2-4)

Question 6

Outline the sympathetic nervous system innervation to the gut

Answer 6

• fight or flight
• thoracolumbar (T5-L2) outflow to gut to the sympathetic chain > greater, lesser +least splanchnic nerves > organs

Question 7

Outline the enteric nervous system

Answer 7

• two main plexes:
• submucosal (Meissner’s) plexus in submucosa > secretions + blood flow
• myenteric (Auberbach’s) plexus in between circular + longitudinal muscle layers > gut motility