Download Digestive System

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 your
body as wastes
Types of Digestion
mechanical 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 churned
chemical 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
Additional Digestive Organs
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
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