Stomach

Question 1

Cells of the stomach (and their roles)

Answer 1

Mucous neck cells - secrete mucous (found in neck of gland)

Goblet cells (mucus)

Parietal cells (gastric acid & intrinsic factor)

ECL cells (histamine)

Chief cells (pepsinogen)

D cells (somatostatin - inhibits acid secretion)

G cells (gastrin - stimulates acid secretion)

Question 2

Four regions of the stomach

Answer 2

1. Cardia
2. Fundus
3. Body
4. Pyloric region (antrum; pyloric canal > terminates at the pylorus, which is surrounded by the pyloric sphincter)

Question 3

Where does stomach receive innervation from?

Answer 3

Parasympathetic - from vagus nerves

Sympathetic nerves - celiac ganglia

Question 4

What are enteroendocrine glands?

Answer 4

Secrete hormones and paracrine messengers that regulate digestion.

Question 5

Role of intrinsic factor

Answer 5

Essential in the absorption of vitamin B12 by the small intestine. Intrinsic factor binds vitamin B12 and the complex is then taken up by receptor-mediated endocytosis. Vitamin B12 is needed for synthesis of haemoglobin

Question 6

What are the four layers of the GI tract?

Answer 6

(Innermost) - Mucosa - contains pits with glands in the stomach.
Submucosa
Muscularis externa (oblique, circular & longitudinal)
(Outermost) - Serosa