Mechanical Digestion Flashcards
The Digestive System
What is mechanical digestion?
The physical breakdown of good particles, involving the following processes in the mouth, stomach and small intestine.
What is the role of teeth in breaking down food?
The teeth cut, tear and grind the food.
What are the different types of teeth and their functions?
- 4 incisors are used for biting or cutting.
- 2 canines used for tearing.
- 4 premolars and 6 molars have broad crowns ideal for crushing and grinding food.
What is role of the churning action in the stomach?
The churning action in the stomach breaks the food down further.
How does the stomach allow churning to happen?
The muscles in the stomach enable it to contract in a variety of ways to churn the food and mix it with the stomach juices until the food is converted into chyme.
What is peristalsis?
The contraction of successive bands of circular muscle that causes the constriction to move in a wave
What is the role of peristalsis in moving food through the digestive tract?
As the lump of food enters the pharynx and oesophagus, the circular muscle behind it contracts to narrow the tube and the circular muscle around and in front of the ball relaxes.
This movement pushes the food in front of it, assisted by the secretion of mucus that lubricates the inner lining.
What is bile?
Is produced by the liver but stored in the gall bladder and secreted into the small intestine via the bile duct.
What does bile contain?
It contains no digestive enzymes but has bile salts important for digestion of fats.
What is the function of bile in emulsifying fats?
They emulsify fats into tiny droplets, which is a form of MD that increases the surface area on which lipases can act to chemically break down fat.
