ACTIVITY — Digestive System
Changes in consistency and form of food
- Digestion allows food to be broken down mechanically and chemically to facilitate the release of nutrients throughout the body. This process begins in the mouth, where mechanical digestion takes place. Through chewing, the food then mixes with saliva and its enzymes as chemical digestion occurs. The bolus (soft mass) is then being pushed by the tongue to the esophagus, which is being broken down into smaller molecules due to churning action. Peristalsis takes place, which then allows the food to reach the stomach, where the bolus is converted into chyme. The chyme (fluid-like form) then enters the small intestine, where digestive juices from the pancreas and liver mix with it. Once the food has been digested, absorption into the blood occurs. Undigested food goes into the large intestine, where it undergoes water and mineral absorption. Meanwhile, feces (solid/semisolid waste) are eliminated from the anus.
Process of nutrient absorption from food
- The small intestine's lining cell membranes allow the simple chemicals created by chemical digestion to reach the blood or lymph capillaries. This occurs through the following: (1) the pancreatic, liver, and intestinal digestive fluids combine with food as it is pushed forward by the small intestine's muscles; (2) the absorption of digested nutrients into the circulation; and (3) the body's cells receive their nutrition from the blood, where they provide numerous benefits such as provision of energy and maintenance of health. Aside from the small intestine, the large intestine also plays a role in the absorption of other vitamins such as vitamin K.