Lacteals absorb and transport dietary lipids

Steps:

• Identify vessel X as a lacteal, the central lymphatic vessel in intestinal villi.
• Recall that fats are digested into fatty acids and monoglycerides in the small intestine.
• These lipids are reassembled into chylomicrons and absorbed into lacteals.
• Chylomicrons enter the lymph system for circulation, avoiding direct liver entry.

Why D is correct:

• Lacteals are specialized lymphatic capillaries that transport emulsified fats (fatty acids and glycerol as chylomicrons) directly into the lymphatic system per standard digestive physiology.

Why the others are wrong:

• A: Amino acids are water-soluble nutrients absorbed into blood capillaries, not lacteals, for hepatic processing.
• B: Deoxygenated blood reaches villus cells via venous networks, not the fat-specific lacteals.
• C: Oxygenated blood is supplied to villus cells by arterial capillaries, distinct from lymphatic lacteals.

Final answer: D