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