Question

For each of the factors affecting intestinal activity A–E, select the most appropriate response from the list below. 

1. Inhibition of gastric secretion. 

2. Stimulation of gastric secretion. 3. Increase in gastric motility. 

4. Decrease in gastric motility. 

5. Gall bladder contraction. 

A. CCK-PZ. 

B. Fat in the duodenum. 

C. Pentagastrin. 

D. Blockade of H₂ receptors. 

E. Adrenaline injection.

Answer 1

A. Option 5 Gallbladder contraction. CCK, produced by the mucosal cells in the duodenal wall when fat or other nutrients enter that part of the gut, travels in the blood to the gall bladder so that the bile contents are sent to the duodenum to help in the digestion and absorption of fat. 

B. Option 4 Decrease in gastric motility. Fat in the duodenum slows the transit of gastric contents into the small gut and so slows and delays the digestion of the gastric contents. 

C. Option 2 Stimulation of gastric secretion. Pentagastrin is a pharmacological product containing five of the amino acids in gastrin that can act like gastrin to stimulate gastric secretion. It is used to test the functional efficiency of the gastric mucosa to secrete gastric juice. 

D. Option 1 Inhibition of gastric secretion. Histamine is the neurotransmitter at vagal nerve endings in the stomach and acts on H₂ receptors. Thus H₂ receptor blockers can reduce acid secretion by the gastric mucosa. 

E. Option 4 Decrease in gastric motility. Adrenaline and similar adrenergic agents cause intestinal smooth muscle to relax.