Transcript The Digestive System - Blountstown Middle School

The Digestive System
6th Grade Life Science
Major Functions of the Digestive System
• Break down ingested food
• Put nutrients into the bloodstream
• Remove waste from the body
Organs of the Digestive System
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Mouth- teeth, salivary glands, tongue
Esophagus
Stomach
Small Intestine
Large Intestine
Pancreas
Liver
• Gall bladder
Accessory
Organs
Mouth
• Digestion begins here!
• Teeth and tongue are used in mechanical
digestion- physical breakdown of food
• Saliva and enzymes begin chemical digestionchemical breakdown of food
Esophagus
• Muscular tube that connects mouth to stomach
• Moves food downward by peristalsis, or
muscular contractions
• Epiglottis seals off windpipe during swallowing to
prevent choking
Stomach- Mechanical and
Chemical Digestion
• Muscular pouch that expands to hold your food
• Hydrochloric acid (HCl) and the enzyme pepsin
combine to form gastric juice
• A gummy coating of mucus protects the stomach
lining from the strong chemicals
• Chyme, a thick liquid containing partially
digested food, is produced here
Small Intestine
• Most chemical digestion occurs here!
• Inner surface is covered in villi and microvilli,
millions of tiny finger-like projections that absorb
nutrient molecules from the chyme
• The villi create a large surface area so
as many nutrients as possible can be a
absorbed
• Longest portion of the digestive tract
Large Intestine
• No digestion occurs here
• Water is absorbed from remaining food
• Bacteria feed on material passing through and
produce Vitamins (K) vital to our health
• Waste material, feces, is prepared for elimination
from the body
Rectum
• Stores feces until they can be expelled through
the anus.
The End!