Your Digestive and Excretory Systems Your digestive system breaks down the food you eat into nutrients that your body cells can use as fuel. As that fuel is burned, the production and use of energy leaves behind waste products. Your excretory system gets rid of some of the wastes your body produces, and helps control your body’s water balance. This system includes the kidneys and the bladder.

The Digestive Process Digestion begins in the mouth. Teeth crush, tear and grind food- saliva adds digestive enzymes- and the crushed food enters the esophagus. Muscles contract and relax, pushing the food along. In the stomach, strong acid and enzymes turn the food into a thick paste called chyme.

The Digestive Process (cont.) The majority of digestion takes place in the small intestine. From here, digested food particles are absorbed into the blood. Food particles that cannot be digested enter the colon, or large intestine. When the colon becomes full, the waste is passed out of the body.

The Kidneys and Bladder The body needs to control its water and salt supplies at all times. The excretory system helps keep this balance correct. The kidneys are a filtering system for the blood. At certain times, the kidneys remove mostly water from the blood. At other times, the kidneys remove mostly salts. Liquid waste material from the kidneys is stored in the bladder as urine. When the bladder is full, the urine is passed out of the body. Excretion is the name of the process of removing liquid wastes from the body.

Keeping Your Digestive and Excretory Systems Healthy 1)Eat a balanced diet. 2)Eat regular meals at regular times. 3)Chew food slowly. 4)Drink plenty or water.