Histology

Question 1

Name the layer of the gut tube from innermost to outermost

Answer 1

1. Mucosa: Composed of:
   A) Epithelia
   B) Lamina Propria
   C) Muscularis Mucosae

2.Submucosa

3. Muscularis Externia
   A) Inner Circular Muscular layer.
   B) Outer longitunidal layer
4. Adventitia vs Serosa

Question 2

What’s the difference between adventitia and serosa?

Answer 2

Adventita - loose layer of connective tissue covering the external surface of an organ.

Serosa - smooth membrane, composed of simple squamous epithelia and sparse layer of connective tissue covering the external surface of the viscera.

Question 3

What epithelia is present in the oesophagus

Answer 3

Stratified squamous non-keratinised epithelia.

Question 4

Describe the histology of the stomach

Answer 4

Gastric Pits composed of
Parietal Cells- Secretion of HCL
Chief Cells - base of glands - secrete pepsinogen
Simple columnar epithelia
Gastric Glands in the mucosa

Question 5

Describe the histology of the small intestines

Answer 5

Presence of Villi, crypts of lieberkuhn (gastric pits of the stomach, containing paneth cells) that secrete intestinal juice and peyers patches (lymphoid nodules) Brunner’s glands.

Question 6

The purpose of the sections of the small intestine

Answer 6

Duodenum- site of main chemical digestion.
Jejunum - Main site of absorption and proteins.
Ileum - absorption of vitamin b12, bile salts and any products of digestion not absorbed by the jejunum.

Question 7

What are duodenal glands ?

Answer 7

Brunner’s glands (duodenal glands) to produce mucous-like alkaline secretion (bicarbonate secretion).

Question 8

What are peyers patches

Answer 8

Organised lymph nodules found in the small intestine.

Question 9

What are intestinal villi?

Answer 9

Tiny finger-like projections that protrude from the epithelia mucosa.

Question 10

Origin of intestinal enzymes and examples

Answer 10

The pancreas via the pancreatic duct into the small intestine in response to cholecystokinin.

Question 11

Describe secretin

Answer 11

Activated by gastric acid from prosecretin and synthesised by S-cells in the duodenum.

Secretin works on the acinar cells.

Produced by the duodenal mucosae, acts on the pancreas to release bicarbonate and water.

It also reduces gastric acid secretion.

Question 12

Histology of the ileum

Answer 12

Villi and Peyer’s Patches

Question 13

Histology of the large intestine

Answer 13

Think mucosa, crypts, mucous secreting cells. No villi