THE DIGESTIVE SYSTEM

FUNCTIONS

Absorption

Digestion

Ingestion

Elimination

TYPES

Mechanical digestion

Chemical digestion

Physically breaking the food

Example

Churning (in stomach)

Chewing (in mouth)

Chemical reactions that break down food

Example

Gastric acid help breakdown protein (in stomach)

Food mixes with saliva and breakdown carbohydrates (in mouth)

MAJOR DIGESTIVE ENZYMES

Amylase

Lipase

Protease

Location

in stomach

in duodenum

Substrate digested

Protein

Location

Substrate digested

Location

Substrate digested

in mouth

in duodenum

Starch

in duodenum

Fat

ORGANS

Digestive tract

Mouth

Teeth and the tongue mechanically digest food

Salivary glands produce saliva, amylase begin to breakdown carbohydrates

Esophagus

The food is shaped into a bolus and swallowed into the esophagus

The bolus is pushed through the esophagus by peristalsis (wave of muscle contractions)

Stomach

Performs a chemical breakdown due to enzymes and hydrochloric acid

The stomach wall churn the food to mix with Gastric acid

Small intestine

Chemical digestion of proteins, carbohydrates, nucleic acids, and fats occurs in duodenum

The liver, gallbladder, and pancreas release digestive fluids into the duodenum

Nutrients are absorbed from the jejunum and ileum

Large intestine

Water, minerals, and vitamins are absorbed

The semisolid waste is pushed into the rectum.

Muscles in the rectum control the release of the waste, called feces, through the anus

Accessory digestive organs

liver

pancreas

salivary glands

teeth

tongue

gallbladder