Chapter 9 - The Digestive System Flashcards
What are the basic activities of the digestive system?
- Ingestion of food and water
- Mechanical digestion of food
- Chemical digestion of food
- Movement of food along the alimentary canal
- Absorption of digested food and water into the blood and lymph
- Elimination of material that is not absorbed
What is the alimentary canal?
The continuous tube that runs from the mouth to the anus, together with digestive organs it makes up the digestive system.
What does the lining of the alimentary canal do?
It is the surface through which nutrients are absorbed.
What is digestion?
The process in which carbohydrate, protein and fat molecules are broken down into products small enough to be absorbed into the cells and blood.
What is ingestion and where does it occur?
It is thee intake of food and occurs at the mouth.
Mechanical digestion: mouth
Breaks food into smaller particles by chewing.
Mechanical digestion: stomach
Waves of contraction churn food.
Mechanical digestion: small intestine
Muscular contractions churn food; bile salts emulsify lipids.
What it the function of the mouth cavity?
- mechanical digestion by teeth
- chemical digestion of starch by saliva
What is the function of the salivary glands?
- produces saliva
- moistens food
- begins digestion by breaking down starch with the enzymes amylase (ptyalin)
What is the function of the liver?
- produces bile
What is the function of the gall bladder?
- stores bile
What is the duodenum?
The first part of the small intestine
What is the function of the oesophagus?
Carries food from the mouth to the stomach.
What is the function of the pyloric sphincter?
Band of circular muscle that regulates flow of material from the stomach to the duodenum.
What is the function of the pancreas?
Produces pancreatic juice containing enzymes for digesting proteins, lipids and nucleic acids.
What is the function of the small intestine?
- lining secretes intestinal juice which contains enzymes
- internal surface is lined with villi for absorption of digested food
Where does the digestion of carbohydrates occur?
- mouth
- small intestine
Where does the digestion of fats occur?
- small intestine
Where does the digestion of proteins occur?
- stomach
- small intestine
Which enzyme helps digest carbohydrates?
Amylase
Which enzyme helps digest fats?
Lipase
Which enzyme helps digest proteins?
Protease
What is the final product of digested carbohydrates?
Glucose (monosaccharides)
What is the final product of digested fats?
Fatty acid and glycerol
What is the final product of digested proteins?
Amino acids
