Week 6 - Gastrointestinal

Question 1

What are the actions of the stomach?

Answer 1

Digestion
Secretion
Absorption
Motility

Question 2

What is the mechanism of Digestion?

Answer 2

Food entering the gut is broken down by secretion

Question 3

What is the mechanism of Secretion?

Answer 3

Agents released from the exocrine glands

Question 4

What is the mechanism of Absorption?

Answer 4

Transport across the lumen into the blood or lymph

Question 5

What is the mechanism of Motility?

Answer 5

Contractions of smooth muscle of the gut wall mix the content and propel it from
mouth to anus

Question 6

What is the neuronal control of increased acid secretion?

Answer 6

• central vagal tone
• visual clues and stomach reflexes
• muscle contractions

Question 7

What hormomes control acid secretion?

Answer 7

• Gastrin
• ACh (M)
• Histamine (H2)

Question 8

How do hormones control acid secretion?

Answer 8

• stimulate parietal cell H+ release

- stimulate chief cell pepsinogen release

Question 9

What are the 3 main cell types controlling acid secretion? Giving examples

Answer 9

• G-cells - Gastrin
• ECL cells - enterochromaffin
• Parietal cells - HCl production and release

Question 10

What are the actions of G-Cells?

Answer 10

• bind to CCK receptors on ECL and parietal cells

- increase histamine and acid production

Question 11

What are the actions of ECL-Cells?

Answer 11

• neuroendocrine cells contain histamine

- maintain basla histamine/acid drive