Purpose of the Digestive System

- the break down of food into nutrients digestion: process that breaks down food into small

molecules so that they can be absorbed and moved into the blood

-the blood transports the nutrients to all parts of the body so it can be used to make energy- unused molecules pass out of yourbody as wastes

Types of Digestionmechanical digestion: the breaking, crushing and mashing

of food- starts in the mouth when food is chewed- continues in the stomach when food is mixed and

churnedchemical digestion: large molecules are broken down into

nutrients using chemicals called enzymes

- starts in the mouth with saliva mixing with food- continues in the stomach with acids- finishes in the small intestine

Digestive Tract- mouth: teeth chew (mechanical digestion) and the tongue

pushes food around - saliva breaks down food (chemical digestion)

- esophagus: muscular organ uses peristalsis: wavelike movement to squeeze food

to stomach- stomach: muscular baglike organ that continues

mechanical and chemical digestion - creates a soupy mixture called chyme

- small intestine: chemical digestion is finished here; food has

been broken down into nutrients, which are absorbed into the blood

- large intestine: main job is to absorb water from undigested food mass - undigested materials become solid waste

(feces), which is stored in the rectum and is expelled through the anus

liver: makes a green liquid called bile, which is used to digest fat

gallbladder: stores bile produced by the liver

pancreas: makes materials that neutralize the acid in chyme

and further chemically breakdown proteins

Additional Digestive Organs

Liver

Digestive Diseases Heartburn: results from backflow of

chyme from the stomach into the esophagus, which causes a burning sensation in the chest or throat Gastric Ulcer: an open sore on the stomach lining caused by bacteria Colon Cancer: affects part of the large intestine and is caused by cells dividing uncontrollably to form a tumor Constipation: body does not get enough fiber, water or exercise so the feces become dry, which makes it hard to get rid of the solid waste Diarrhea: indigestible food moves too quickly through the large intestine, so water is not removed and solid waste becomes a liquid