Which process involves nutrient molecules passing through the wall of the digestive system into the blood?

Which process involves nutrient molecules passing through the wall of the digestive system into the blood?

• A. Absorption
• B. Ingestion
• C. Secretion
• D. Elimination

Answer: (A)

Nutrient absorption is the process by which digested nutrients cross the wall of the digestive tract into the bloodstream. The small intestine’s lining is designed to maximize this transfer, with many villi and microvilli increasing the surface area. Digested nutrients like sugars, amino acids, and other small molecules move through the epithelial cells by diffusion or active transport, then enter the capillaries in the lining and travel to the liver via the portal vein. Fats follow a slightly different route and initially enter the lymphatic system, but the overall idea is that absorption is about moving nutrients across the intestinal wall into circulation. Ingestion is taking in food, secretion is releasing digestive juices, and elimination is removing undigested waste.

Nutrient absorption is the process by which digested nutrients cross the wall of the digestive tract into the bloodstream. The small intestine’s lining is designed to maximize this transfer, with many villi and microvilli increasing the surface area. Digested nutrients like sugars, amino acids, and other small molecules move through the epithelial cells by diffusion or active transport, then enter the capillaries in the lining and travel to the liver via the portal vein. Fats follow a slightly different route and initially enter the lymphatic system, but the overall idea is that absorption is about moving nutrients across the intestinal wall into circulation. Ingestion is taking in food, secretion is releasing digestive juices, and elimination is removing undigested waste.