Digestive System Flashcards
Digestion
This is breaking down food mechanically and chemically into small soluble substances.
Absorption
This is the movement of soluble molecules into the blood. It is helped by the large surface area, and the presence of villi and microvilli
Assimilation
When the small soluble molecules become part of the cells, ie are used for growth and repair and energy.
Egestion
This is how undigested food (faeces) leave the body
Mechanical digestion
Food is broken up by the teeth and tongue in the mouth and churned in the stomach by muscular movements
Chemical digestion
Food is broken down by enzymes.
Amylase
This enzyme breaks down starch into sugar. Eg bread, potatoes
Protease
This enzyme breaks down proteins into soluble amino acids. Eg meat and fish
Lipase
This enzyme breaks down fats and oils into smaller particles. Eg butter
Simple sugars
Glucose is a soluble sugar that can be absorbed into our blood and transported to every cell in the body.
Amino acids
These are small soluble protein molecules. There are 20 different types.
Fatty acids and glycerol
These are the building blocks of fats.
The mouth
Food is mechanically digested by the teeth.
Food is mixed with saliva which lubricates the food for swallowing.
The oesophagus
Food is pushed along this tube from the mouth to the stomach by waves of muscles in a process called peristalsis
Peristalsis
This helps to move food down the oesophagus. It works by the muscles above the food contracting and those below the food relaxing, squeezing the bolus of food into the stomach.