THE DIGESTIVE SYSTEM

The Digestive System

• Function

• Parts

• How the parts work together

Function of Digestive System

•Absorption of food• Removal of waste

into bloodstream•Break down food

to get nutrients to cells

Organs

Breaking down food• Mouth• Stomach• Small intestines• Large intestines• Rectum• Peripheral organs

Mechanical Digestion• Physically breaking

something apart

–Teeth

–Muscles of the stomach

Chemical• Enzymes and acids added

–break down big food molecules

Enzyme

Mouth

• Teeth

• Salivary glands- starts breaking down and starts digestion

• Tongue

Mouth

•Mechanical

•Chemical

Mouth - Mechanical• Teeth

– Incisor– Canine– Molar– Pre-Molar

Mouth - Chemical• Saliva

– Salivary amylase•Breaks down starches into sugars

Mouth

• Teeth

• Salivary glands- starts breaking down and starts digestion

• Tongue

Esophagus

Stomach

• Grinds and dissolves food

• Main part of digestion

Stomach• J- shaped organ

• Can hold 2 liters of food

• Most mechanical digestion occurs here

Stomach - Mechanical• Strong muscles grind up

food particles

Stomach - Chemical• Pepsin

– proteins amino acids

•Hydrochloric Acid

-Kills bacteria

- Provides good environment for pepsin

Small Intestine

• ~ 6 meters (20 feet) long

• ~ 2 or 3 cm (1 inch) wide

• Almost all chemical digestion occurs here

Small Intestine

• Most chemical digestion occurs here.

• Absorption of nutrients occurs here.

Intestines (Bowel)

• Large

• Stores, Compacts, and Eliminates indigestible material

Fast Facts About Villi

• Stretch out- 18ft

• Flatten surface- larger than a tennis court

Villi absorb nutrients

Small intestine - Chemical

• Bile– breaks fats into small particles– made in liver

Small intestine - Chemical

• Trypsin – made by pancrease–breaks down proteins

Large intestine

• Bacteria – cellulose - vitamin K• Absorbs water• Compacts stool

Rectum

• Stores feces• Leaves rectum and body

through the anus

Salivary Glands

• Produce – salivary amylase– starches simple sugars

Pancreas

• Produces trypsin and other enzymes to break down proteins

Liver

• Produces bile to break down fats

Gall Bladder

• Stores bile from liver

• Controls release of bile small intestine.

How the Digestive System works

•Break down food

•Absorption of food

•Getting rid of waste

Organs

Breaking down food• Mouth• Stomach• Small intestines• Large intestines• Rectum• Peripheral organs

Mechanical Digestion• Physically breaking

something apart

–Teeth

–Muscles of the stomach

Chemical• Enzymes and acids added

–break down big food molecules

Mouth

• Teeth

• Salivary glands- produce salivary amylase

• Tongue

Mouth

• Teeth

• Salivary glands- starts breaking down and starts digestion

• Tongue

Esophagus• Connects mouth to

stomach

• Peristalsis – muscles move food to stomach.

Esophagus

Stomach• mechanical digestion -

grinding• chemical digestion

–pepsin - proteins amino acids–amylase - starches sugars

Stomach

• Grinds and dissolves food

• Main part of digestion

Small Intestine

• ~ 6 meters (20 feet) long

• ~ 2 or 3 cm (1 inch) wide

Small Intestine

• Absorption of nutrients occurs here.

Small intestine - Chemical

• Bile– breaks fats into small particles– made in liver

Fast Facts About Villi

• Stretch out- 18ft

• Flatten surface- larger than a tennis court

Gall Bladder

Small intestine - chemical

• Trypsin – made by pancreas–breaks down proteins

Large intestine

• Bacteria – cellulose - vitamin K• Absorbs water• Compacts stool

Intestines (Bowel)

• Large

• Stores, Compacts, and Eliminates indigestible material

Rectum

• Stores feces• Leaves rectum and body

through the anus

The Digestive System

• Function

• Parts

• How the parts work together