O Levels Biology (5090)•5090/12/M/J/19

Explanation
Lipid Absorption in Small Intestine Villi
Steps:
- Digestion breaks lipids into micelles for absorption across enterocyte membranes.
- Inside enterocytes, lipids reform into chylomicrons.
- Chylomicrons exit enterocytes via exocytosis into the interstitial space.
- Chylomicrons enter lacteals for lymphatic transport to bloodstream.
Why A is correct:
- Lacteals are lymphatic capillaries in villi that absorb and transport chylomicrons, as lipids are insoluble in blood and require lymphatics per digestive physiology.
Why the others are wrong:
- B: Blood capillaries absorb water-soluble nutrients like amino acids and sugars, not lipids.
- C: Goblet cells secrete mucus for protection, not absorption.
- D: Central lacteal is the target, but if D is muscularis, it aids motility, not lipid transport.
Final answer: A
Topic: Absorption and assimilation
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