Human Nutrition and Digestion Overview

The process of breaking down food into smaller molecules that can be absorbed and used by the body.

The breakdown of food by physical means, like chewing or churning.

The breakdown of food using enzymes, like amylase in saliva.

The chemical breakdown of carbohydrates in the mouth.

The process of the stomach muscles contracting and relaxing to mix food with digestive juices.

A strong acid produced in the stomach that helps kill bacteria, loosen food, and activate pepsinogen.

A protein produced in the stomach that gets activated by HCl to form pepsin.

A protective mucus layer in the stomach that prevents self-digestion.

The large intestine is responsible for absorbing water, producing vitamins, and eliminating waste.

The caecum and appendix are considered 'vestigial' organs, meaning that they have no known function in humans or have lost their function over time.

Symbiotic bacteria in the colon provide several benefits, including the production of vitamins B and K and competing with harmful bacteria.

A heterotroph is an organism that cannot make its own food and needs to consume other organisms for energy.

Enzymes are biological catalysts that speed up chemical reactions in the body. Three key catabolic digestive enzymes are amylase, lipase, and pepsin.

The first part of the small intestine, where chyme from the stomach enters. It's the site where enzymes from the pancreas and bile from the liver mix with food.

A substance produced by the liver and stored in the gallbladder. It emulsifies fats, increasing their surface area for digestion, and neutralizes acidic chyme.

A leaf-shaped gland that secretes pancreatic juice into the duodenum. This juice contains enzymes (lipase, amylase) to breakdown fats and carbohydrates, as well as sodium bicarbonate to neutralize chyme.

The second part of the small intestine, where most nutrient absorption occurs. It features villi and microvilli for increased surface area and a rich blood supply for efficient transport.

Finger-like projections lining the ileum. They increase the surface area for absorption of nutrients by diffusion.

The process of muscle contractions that push food through the digestive tract.

A small lymphatic vessel within each villus. It absorbs fatty acids and glycerol, transporting them to the lymphatic system.

A blood pathway that begins and ends in capillaries. The hepatic portal vein carries nutrients from the small intestine to the liver, where they are processed and stored.