Question

Lacteal present in the villi of the small intestine
A. Help to absorb fatty acids and glycerol
B. Secrete enzymes for digestion
C. Secrete hormones
D. Help to absorb proteins

Answer 1

Hint: The cells lining the villi produce numerous microscopic projections called microvilli which gives a brush border appearance to it. These modifications increase the surface area enormously. These villi are supplied with a network of capillaries and a large lymph vessel called the lacteal.

Complete answer:
Fatty acids and glycerol being insoluble, cannot be absorbed into the blood. They are first incorporated into small droplets called micelles which move into the intestinal mucosa. They are re-formed into very small protein coated fat globules called the chylomicrons which are transported into the lymph vessels (lacteals) in the villi.
These lymph vessels ultimately release the absorbed substances into the bloodstream.
Help to absorb fatty acids and glycerol :- the fatty acids are insoluble so they are not absorbed by blood. That’s why they are transported to lacteals for absorption. So this option is correct.
Secrete enzymes for digestion :- enzymes are secreted usually by the organs and not vessels. Thus this option is not correct as lacteal is a vessel.
Secrete hormones :- hormones are usually secreted by glands and secretions are poured into blood thus vessels are not needed. So the option is wrong.
Help to absorb proteins :- proteins are first converted into amino acids for absorption and amino acids are soluble in water so they do not require lacteals. Hence this option is incorrect.

Our required answer is A) Help to absorb fatty acids and glycerol.

Note: The wall of the intestine has thin layers of longitudinal and circular muscles. Mucosa has folds called plicae circular and villi towards the lumen of the intestine. Epithelial cells lining the villi have microvilli which further increase the absorptive area.