Digestive System

Function Break down food into particles the body can use Particles are absorbed into blood and carried throughout body Wastes are removed from the body

Organs Involved 1. Mouth 2. Esophagus 3. Stomach 4. Pancreas 5. Liver 6. Gallbladder 7. Small Intestine 8. Large Intestine 9. Rectum

Digestion-process where body breaks down food 2 Kinds: 1) Mechanical-physically broken down 2) Chemical-chemicals break food down –Enzymes-proteins that speed up chemical reactions in the body »Pepsin-breaks down protein »Amylase-breaks down starch

Absorption-nutrients pass though wall of digestive system into blood. The circulatory system will then carry the nutrients to the cells of the body. Saliva-fluid released by mouth; contains enzymes

The Mouth Mechanical digestion starts with teeth Saliva mixes with food moistening Chemical digestion also starts breaking down starch into sugar Salivary Glands-produce Saliva

Esophagus Muscular tube that connects mouth to stomach, lined with mucus 2 openings at back of mouth-one to trachea, one for esophagus Epiglottis-flap covering trachea Peristalsis-involuntary waves of muscle contractions to push food along

Stomach J-shaped Pouch Mechanical digestion occurs here when strong muscles squeeze food. MOST mechanical digestion occurs here. Chemical digestion occurs at same time-acids and other chemicals break down food

Stomach cont… Contains hydrochloric acid-a very strong acid which would burn through clothing but without this acid, your stomach would not work properly. Has a mucus lining-coats and protects your stomach Your stomach produces a new lining every 2 days.

Stomach cont… Heartburn is when some of the stomach acid starts to move back up the esophagus causing a burning sensation in chest. Stomach ulcer-when a person produces too much stomach acid and it burns a hole in the stomach lining.

Small Intestine Most chemical digestion occurs and absorption of nutrients takes place Covered with villi-tiny finger shaped structures with capillaries inside Capillaries inside villi pick up nutrients so blood can carry to rest of body

Cross Section of Small Intestine

Liver, Gallbladder and Pancreas (Food does not pass through these organs) Liver-largest and heaviest internal organ inside the body –Produces bile-substance that breaks down fat Gallbladder-stores bile Pancreas-produces chemicals that break down starches, proteins and fats

Large Intestine Removes water from undigested material Contains helpful bacteria that produce vitamins

Large Intestine Cont…

Rectum Waste is compressed into a solid form “Holding tank” for wastes until they can be removed Removed from the body through the anus-a muscular opening at the end of the rectum