L5 - HARC GI 2

Question 1

State the 3 parts of the primitive gut tube and which parts they develop into?

Answer 1

Foregut

• oesophagus
• 2nd part of duodenum
• accessory organs (liver, gall bladder, pancreas)

Midgut
- 2nd part duodenum to3/4 transverse colon

Hindgut
- 3/4 transverse colon to superior

Question 2

Describe some key microanatomical features of mucosa

Answer 2

1. Circular folds
   - increased SA
   - slow chyme flow
2. Villi & Microvilli
   - massive SA
   - abundant in first 2/3rd of S.I, where most absorption occurs
3. Intestinal glands
   - enterocytes, goblet cells, paneth cells, multipotent stem cells to replace eroded epithelia
   - produce intestinal juices rich in digestive enzymes

Question 3

Position of submucosal plexus?

Answer 3

Between submucosa and circular muscle.

Question 4

Position of myenteric plexus?

Answer 4

Between circular and longitudinal muscle.