Digestive System Chapter 12

Digestion The human body breaks down food through the process of digestion. Food enters the digestive system through the mouth. The mouth is where digestive system starts

Digestion (cont.) The esophagus is a long tube that connects the mouth to the stomach—a flexible baglike organ that contains enzymes that break down food into smaller parts to be used by the body. Food mixes with gastric juices in the stomach

Digestion (cont.) The small intestine has two functions—digestion and absorption. Small intestine is approximately 22 feet long in adults Nutrients are absorbed by the body through the small intestine. Food can spend up to 4 hours in the small intestine

Digestion (cont.) The liver makes bile and the pancreas makes enzymes, both of which break down food in the small intestine. The liver removes harmful substances from blood

Digestion (cont.) The large intestine receives solid waste from the small intestine. The large intestine absorbs excess water from the waste material. The large intestine is about 5 feet long. The rectum of the large intestine stores the solid waste until the waste is expelled from the body.

Digestion (cont.) Some foods, like insoluble fiber, that are not digested leave the body through the rectum.

Digestion (cont.) Nutrients are the parts of food used by the body to grow and survive. The organs that help with absorption of nutrients is the pancreas, the liver, and the gallbladder. Proteins, fats, carbohydrates, vitamins, and minerals are all nutrients. Calories are a measure of the amount of energy in food.