Digestive System Flashcards
What is digestion?
The process in which carbs, protein and fat molecules are broken down to products small enough to be absorbed into the blood and into the cells.
The organs of the digestive system are structured and arranged so that they can carry out 6 basic activities. List them.
Note: be careful of steps 4 and 5
1) ingestion of food and water
2) mechanical digestion of food in mouth
3) chemical digestion of food in stomach
4) movement of food along the alimentary canal
5) absorption of digested food and water into the blood and lymph
6) elimination of material that is not absorbed.
What does the digestive system do?
It extracts nutrients from the food we eat and absorbs them into the body for use by the cells.
What nutrient and enzyme is active in the stomach and small intestine?
Nutrient is protein and enzyme is protease.
What nutrient and enzyme is active in the small intestine?
Nutrient is fat and enzyme is lipase.
What nutrient and enzyme is active in the mouth and small intestine?
Nutrient is carbs and enzyme is amylase.
Lipids ——> _______
Protease ——–> _______
Amylase ——–> _______
Lipids to lipase
Protease to proteins
Amylase to carbohydrates
Which enzyme is active in the mouth?
Ptyalin
Mechanical digestion occurs through enzymes in gastric juice. What is one of the main enzymes in the stomach?
Pepsin
What is the function of the pancreas?
- regulate glucose levels
- releases insulin and glycogen which decrease/increases blood sugar levels.
What is peristalsis?
Contraction of successive bands of circular muscle. This constriction moves in a way along the oesophagus, pushing the food in front of it. This wave of construction is called peristalsis.
What is the function of mucosa in the lining of the stomach?
The lining in the stomach is specialised for the secretion of gastric juice, a digestive juice that is responsible for chemical digestion in the stomach.
Nutrients are absorbed though the internal surface of the small intestine. A large SA is required. How is a large SA achieved?
- small intestine is 6m long
- mucosa has folds that extend into the interior
- villi extend the SA
- the cells that cover the villi have tiny microscopic projections from their external surfaces (microvilli)
What is the difference between elimination and excretion?
Elimination - removal of faeces (defaection)
Excretion - the removal of metabolic wastes
What gives faeces its colour?
Faeces contain water, undigested food material, bacteria, bile pigments and the remains of cells that have broken away from the internal lining of the alimentary canal, giving faeces its colour.
