Digestion

Digestion is the process by which the body breaks down food into smaller components (molecules) so that it can be absorbed and used by the body. This process starts in the mouth and continues through the digestive tract.

Mechanical digestion: This is the physical breakdown of food. It begins with chewing (in the mouth) and continues with the churning action of the stomach, which breaks food into smaller pieces to increase the surface area for enzymes to act on.

Chemical digestion: This is the breakdown of food by enzymes and acids. In the mouth, salivary enzymes start to break down carbohydrates. In the stomach, gastric juices (including hydrochloric acid and digestive enzymes like pepsin) further break down food, especially proteins. In the small intestine, bile from the liver and digestive enzymes from the pancreas help break down fats, proteins, and carbohydrates into simpler molecules

Absorption

Absorption is the process by which the nutrients from digested food are taken into the bloodstream or lymphatic system, allowing the body to use these nutrients for energy, growth, and repair.

Small intestine is the main site of absorption. After food is broken down into small molecules (like amino acids, fatty acids, glucose, vitamins, and minerals), these molecules pass through the walls of the small intestine into the blood vessels or lymph.

The walls of the small intestine are lined with tiny, finger-like projections called villi, which increase the surface area for absorption. On these villi are even smaller hair-like structures called microvilli, which further enhance the absorption process.

Once absorbed, nutrients travel through the bloodstream to various parts of the body where they are used for energy, growth, or repair. Fats are absorbed into the lymphatic system and eventually reach the bloodstream.