Which process moves nutrients from the digestive tract into the bloodstream?

Which process moves nutrients from the digestive tract into the bloodstream?

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

Answer: (A)

The main idea here is how nutrients actually cross from the gut into the body’s circulation. Absorption is the process by which digested nutrients are taken up across the lining of the small intestine and into the bloodstream (and, for fats, into the lymphatic system first before joining the blood). Most nutrient absorption happens in the small intestine—especially the duodenum and jejunum—through various transport methods: some molecules diffuse directly, others use facilitated diffusion, and many require active transport, often linked to sodium gradients. Once inside the enterocytes, nutrients enter the capillaries in the villi and are carried via the hepatic portal vein to the liver for processing. Ingestion is simply taking in food, secretion is the release of digestive juices, and elimination is excretion of wastes. So the process described is absorption.

The main idea here is how nutrients actually cross from the gut into the body’s circulation. Absorption is the process by which digested nutrients are taken up across the lining of the small intestine and into the bloodstream (and, for fats, into the lymphatic system first before joining the blood). Most nutrient absorption happens in the small intestine—especially the duodenum and jejunum—through various transport methods: some molecules diffuse directly, others use facilitated diffusion, and many require active transport, often linked to sodium gradients. Once inside the enterocytes, nutrients enter the capillaries in the villi and are carried via the hepatic portal vein to the liver for processing. Ingestion is simply taking in food, secretion is the release of digestive juices, and elimination is excretion of wastes. So the process described is absorption.