Unit 6.1 and Option D2 - Digestion etc.

Question 1

What are the components within the alimentary canal?

Answer 1

Mouth, oesophagus, stomach, small intestine, large intestine, anus

Question 2

Give an example of an exocrine gland?

Answer 2

Salivary glands - saliva
Gastric glands - gastric juice
Pancreatic glands - pancreatic juice

Question 3

What are the typical elements of an exocrine gland?

Answer 3

Secretory cells to form acini, the proteins formed then exit the cell into the lumen and through the duct cell vessel.

Question 4

What are the role of PPIs?

Answer 4

These drugs regulate the acidity of the hydrochloric acid within the stomach by irreversibly binding to proton pumps in the gastric pits, which stops the efflux of H+ ions. Increasing the pH as H+ ions represent acidity (H+ binds to Cl-). This can help alleviate acid reflux or the formation of gastric infections.

Question 5

What cells produce a protective mucus layer?

Answer 5

Goblet cells

Question 6

What cells produce hydrochloric acid?

Answer 6

Parietal cells

Question 7

What are the colours of Benedict’s reagent and what does it test for?

Answer 7

Tests for reducing sugars
Blue - negative
Yellow - mildly positive
Orange - positive
Red - strongly positive

Question 8

What are the colours for iodine tests and what does it test for?

Answer 8

Starch presence.
Yellow/brown - not present
Blue/purple - present

Question 9

Explain how fats are absorbed into the villi

Answer 9

Fats are broken down from triglycerides into fatty acids and glycerol through emulsification (increasing the SA:V ratio, decreasing the length of time needed for lipase to break it down). The fatty acids diffuse into the epithelial cells where they associate with the Golgi, associating with a protein which turns it into a chylomicron. Chylomicrons then undergo exocytosis towards lacteals where they move to the liver to become either LDLs or HDLs