Introduction to the G.I. Tract

Question 1

What is colonic mass movement?

Answer 1

Powerful sweeping contraction which forces faeces into the rectum

Question 2

What is migrating motor complex (MMC)?

Answer 2

Powerful sweeping contraction from stomach to terminal ileum

Question 3

When is tonic contraction low pressure?

Answer 3

When it involves hollow organs with major storage function e.g. the stomach

Question 4

When is tonic contraction high pressure?

Answer 4

Smooth muscle sphincters

Question 5

Describe the upper oesophageal sphincter

Answer 5

skeletal muscle
relaxes to allow swallowing
closes during inspiration

Question 6

Describe the lower oesophageal sphincter

Answer 6

relaxes to permit entry of food to the stomach

closes to prevent reflux of gastric contents to the oesophagus

Question 7

Describe the pyloric sphincter

Answer 7

regulates gastric emptying

usually prevents duodenal gastric reflux

Question 8

Describe the ilocaecal valve

Answer 8

regulates flor from ileum to caecum

distention of ileum opens, distension of proximal colon closes

Question 9

Internal and external anal sphincters

Answer 9

regulated by the defaecation reflex