Digestion Flashcards
What is the name of the tube that passes through all humans and mammals for absorbing energy from food?
The alimentary canal.
What is ingestion?
Taking food in through the mouth and swallowing.
What is digestion?
Breaking down large insoluble molecules in food into smaller pieces (physical digestion) and smaller, soluble molecules (chemical digestion).
What is absorption?
The movement of small soluble molecules out of the gut and into the blood by diffusion and active transport.
What is egestion?
Passing out undigested food through the anus.
What is assimilation?
Building larger biological molecules from the small soluble molecules, in all cells.
What is the first structure in the alimentary canal?
The mouth.
Where does ingestion take place?
The mouth.
What two types of digestion happen in the mouth?
Mechanical and chemical.
How is food mechanically digested in the mouth and what 2 things does this help with?
Food is broken up into smaller pieces by chewing. This increases the surface area for enzymes and also prevents discomfort when swallowing.
How is food chemically digested in the mouth?
Saliva is released into the mouth by the salivary glands. It makes the food easier to swallow and also contains the enzyme amylase. Amylase breaks down the starch to maltose.
What happens to the amylase in the mouth when it reaches the stomach? Why?
It denatures and stops working because it works best at neutral pH.
What happens to food before it is swallowed?
It is shaped into a ball by the tongue and moved towards the back of the mouth.
What is the ball of food called just before swallowing?
A bolus.
What is the epiglottis?
A flap which blocks the food from entering the trachea.
What process pushes food down from the mouth to the stomach?
Peristalsis.
What 2 sets of muscles work when during peristalsis?
Circular and longitudinal muscles.
How do the circular and longitudinal muscles work during peristalsis?
The circular muscles contract behind the bolus, pushing it along. When the longitudinal muscles contract they make the oesophagus wider.
What is the end product of the digestion of carbohydrates?
Smaller carbohydrate molecules ie glucose.
What is the end product of the digestion of proteins?
Amino acids.
What is the end product of the digestion of lipids?
Glycerol + 3 fatty acids.
Where is amylase found?
The mouth and the duodenum.
Where is pepsin found?
The stomach.