Small Intestine

Question 1

Small Intestine - Location, Structure, Function

Answer 1

Location: Extends from pylorus to the ileocaecal junction.
Structure: divided into 3 parts - duodenum, jejunum, and ileum.
Function: Receives secretions from liver and pancreas. Mechanical and chemical digestion and absorption of nutrients. Transportation of undigested material from stomach to large intestine.

Question 2

Small Intestine - Features

Answer 2

Duodenum
- D1 (superior part)
- D2 (descending part): minor and major duodenal papilla
- D3 (horizontal part)
- D4 (ascending part)
Jejunum 
Ileum

Question 3

Small Intestine - Histology

Answer 3

Circular folds - mucosa + submucosa arranged in permanent folds.
Villi - finger-like projections of the mucosa
- Intestinal crypts between villi
Microvilli - cytoplasmic extensions of mucosal absorptive cells (enterocytes)
- Brush border enzymes embedded in membrane

Question 4

Small Intestine - Cells of Villi and Crypts

Answer 4

Enterocytes
Goblet cells
Enteroendocrine cells
Paneth cells
Stem cells