digestion and absorbtion Flashcards
what happens during digestion
enzymes break down large and insoluble molecules to smaller ones in order to be absorbed into the blood
where does absoption take place
small intesine - ileum
what are the adapations of villi
- one cell thick
- good blood flow of capillaries to maintain concentration gradient
- surrounding muscles to help maximise movement
where are epithilial cells found
in the lining of the small intestine
what does amylase in the salivary gland do
hydrolyses the glycosidic bonds from starch into maltose
what does pancreatic amylase do
hydrolyses glycosidic bonds from starch into maltose
what does membrane bound disaccharidases do
they break the glycosidic bonds to turn a disaccharide into a monosaccharide
what does maltase break down
maltose into 2 alpha glucoses
what does sucrase break down
sucrose into glucose and fructose
what does lactase break down
lactose into glucose and galactose
how are glucose and galactose transported across the epithelial cell
active transport using sodium ions and co- transporter proteins
how are lipids digested
- bile salts attach to the tryglyceride to emulsify large golubular lipids into smaller ones
- lipase then hydrolyses ester bonds and a micelle can form
where are bile salts produced, stored and released
make in the liver
stored in the gall bladder
released into the small intestine
how are lipids absorped
- micelles reach the epithilial cell and break down to diffuse across the membrane
- they are then trasnported to the endoplasmic reticulum where they are joined to make a tryglyceride again
- this tryglyceride is taken to the golgi where it be packed with cholesterol and proteins to make a chlyomicron
- a chlyomicron is a lysosome which is exocyted out of the cell as a vesicle
- the vesicle can be taken away from the small intestine via lacteal capillaries to adipose, cardiac and skeletal muscular tissue
what is the definition of villi
folds found on the cell membrane
