🧪Physio - 1.GI 🧁

Question 1

Digestion

Function of Gastrin, and where is secreted?

Specify organ and which cells

Answer 1

Function: Stimulates gastric juice secretion
Main hormone that increase HCl via parietal cells
Secretion: G-cells in the antrum of the stomach mucosa

**NOTE: **These are **not the same cells **responsible for acid secretion, those are parietal cells

Stomach expansion, protein and caffeine stimulates G-cells to secrete gastrin

Question 2

Function of Secretin, and where is secreted?

Specify organ and which cells

Answer 2

Function: Inhibits gastrin + Stimulates bicarbonate rich pancreatic juice secretion.
Secretion: S-cells onf the duodenal mucosa

Acid chyme stimulates S-cells in duodenum to secrete Secretin

Question 3

Function of CCK, and where is secreted?

Specify organ and which cells

Answer 3

Function: Relaxation of Oddi’s sphincter to promote bile release from gallbladder.
Secretion: I-cells in duodenal mucosa and ileum.

CCK: Colecystokinin

Question 4

Function of GIP, and where is secreted?

Answer 4

Function: Stimulates pancreatic insulin secretion + Inhibits gastric acid secretion.
Secretion: From duodenal mucosa

GIP: Gastric inhibitory peptide

Question 5

Function of Somatostatin, and where is secreted?

Specify organ and which cells

Answer 5

Function: Master inhibitory of everything. Inhibit: gastrin, glucagon and other enzymes. (Promotes HCO3)
Secretion: D-Cells from pancreas (and a bit from stomach)

Low pH Triggers the release of Somatostatin from the pancreas to block gastrin, glucagon and other pancreatic enzymes. (Octreoctide)

Question 6

Function of Motilin, and where is secreted?
| What drug acts on this receptor?

Answer 6

Function: GI Motility
Secretion: Small intestine (M-cells in Jejunum and duodenum)
Erythromycin acts on the Motilin receptor

Question 7

Refeeding Syndrome

What electrolyte abnormality is hallmark of refeeding syndrome?

Answer 7

Hypophosphataemia

Question 8

Refeeding Syndrome

Who is at risk of refeeding syndrome?

Answer 8

Malnourished patients, BMI <16, alcohol abuse, prolonged starvation, chemotherapy.

Question 9

Refeeding Syndrome

Which of the following features does not put a patient at risk of refeeding syndrome?
refeeding syndrome?
A. BMI < 16 kg/m2
B. Alcohol abuse
C. Thyrotoxicosis
D. Chemotherapy
E. Diuretics

Answer 9

Thyrotoxicosis

Diuretics increase the risk of re-feeding syndrome through a process of increasing the risk of depletion of key electrolytes.