Digestion Flashcards
What is the function of the mouth
Mechanical digestion by teeth breaks food into smaller pieces, increasing the surface area for enzymes to work on
Definition of digestion
The mechanical and chemical breakdown of large food molecules into smaller food molecules that can pass into blood.
What do the salivary glands do
They produce amylase which breaks starch down into maltose
What is the function of the oesophagus
Carries food from the throat into stomach by peristalsis, no further enzymes are added.
How does the food not go down the trachea
A flap of skin called the epiglottis prevents food from going down the trachea
How much food can the stomach hold
It can hold 2litres of food and fluid which remains there for 3-4 hours forming a runny liquid called chyme
What is in the stomach and what is the function
Hydrochloric acid kills any microbes in food and drink.
What is produced in the stomach
Pepsin, a type of protease is produced in the stomach as pepsin has an acidic optimum pH
Mucus is also produced to protect the stomach lining from the acid
What will happen to the amylase in the stomach
Amylase will denature and will be digested by the pepsin as it is a protein.
What are the 2 main functions of the small intestine
Further digestion and absorption.
What is digested in the small intestine
All food groups. Starch is broken down by amylase into maltose. Protein is broken down by trypsin into amino acids. Lipids are broken down by lipase into fatty acids and glycerol. Maltose is broken down by maltase into glucose.
What is released from the pancreas
Amylase, protease, lipase and sodium hydrogen carbonate
What is the function of bile
Bile emulsifies lipids. It turns large lumps of lipid into small lumps of lipid which increases the surface area which makes it easier for the lipase to break it down. It also neutralizes acid from the stomach
How does food travel through the oesophagus and small intestine
By the process of peristalsis. The circular muscles contract behind the food and relax in front of the food
How is the small intestine adapted for absorption
The lining of the small intestine is covered with billions of villi. Villi are finger like projections and greatly increase the surface area for absorption. On 1 villus, there may be up to thousands of microvilli on the surface. It also has a large network of blood vessels. The illeum also has a very thin lining
