GI Histology

Question 1

What type of cell covers the oral cavity, oropharynx and laryngopharynx?

Answer 1

Stratified squamous epithelium (which is generally not keratinized)

Question 2

What type of cell covers the nasal cavity and nasopharynx?

Answer 2

Respiratory epithelium

Question 3

What are the four types of tongue papillae?

Answer 3

1. Fungiform
2. Circumvallate
3. Foliate
4. Filiform

Question 4

What is the Gastro-oesophageal junction?

Answer 4

Abrupt transition from stratified squamous epithelium of the oesophagus to the simple columnar epithelium of the cardia of the stomach

Question 5

What do chief cells do?

Answer 5

Digestive enzyme secreting cell

Question 6

What do parietal cells do?

Answer 6

Hydrochloric acid producing cell

Question 7

The mucosa differs in different regions of the stomach. Explain the differences.

Answer 7

Cardia: Deep gastric pits that branch into loosely packed tortuous glands
Body and fundus: shallow gastric pits with long straight gastric glands
Pylorus: deep gastric pits with branched, coiled gastric glands at a higher density than in the cardia

Question 8

What are the three parts of the small intestine?

Answer 8

1. Duodenum
2. Jejunum
3. Ileum

Question 9

Where are Brunner’s glands and what do they do?

Answer 9

Brunner’s glands are located within the submucosa of the duodenum. When stimulated by the presence of chyme they produce a thin, alkaline mucous to neutralize the chyme

Question 10

What are Peyer’s patches?

Answer 10

Areas of relatively large aggregations of lymphoid tissue, particularly in the ileum.

Question 11

What are teniae coli?

Answer 11

In the large intestine the outer, longitudinal smooth muscle is distinct. It is not continuous but is found in three muscular strips called teniae coli.

Question 12

The enteric nervous system has two plexuses. Where are they located, what are they called and what do they do?

Answer 12

1. In the submucosa: submucosal. Controls the muscles of the muscularis mucosae and helps regulate secretion in the epithelium.
2. Between the muscle layers of the muscularis externa: myenteric. Controls gut motility

Question 13

What are the types of cells of the small intestine epithelium?

Answer 13

1. Enterocytes: tall columnar cells with brush border and are principle absorptive cell
2. Goblet cells: produce mucin
3. Paneth cells: found at base of the crypts of Lieberkühn, have a defense function and role in regulating bacterial flora
4. Enteroendocrine cells: produce hormones that contribute to the control of secretion and motility
5. Stem cells: found at the base of the crypts of Lieberkühn, divide to replenish epithelium

Question 14

What are the types of cells of the large intestine epithelium?

Answer 14

1. Absorptive cells: for removal of salts and thereby water

2. Goblet cells: for the secretion of mucus to lubricate the colon