the digestive system Flashcards
name components of digestive system
salivary glands
tongue
epiglottis
oesophagus
liver
stomach
gall bladder
pancreas
duodenum
ileum
colon
rectum
anus
what does saliva consist of
mucin
amylase
mineral salts
peristalsis definition
involuntary construction or relaxation of muscles
what happens in the oesophagus
peristalsis of the circular muscle contracts and relaxes to push food down
what does the liver do
produces bile
what does bile contain (and function of components)
bile salts - aids digestion of fats
mineral salts - neutralise stomach acid
function of gall bladder
stores bile
function of stomach
produces enzymes
stores and digests food
pancreas function
produces pancreatic juices
ileum structure and function
longest part of small intestine
enzymes produced in wall
inner walls have villi
colon (large intestine) function
absorbs water (via osmosis)
absorbs mineral and vitamins
function of duodenum (first section of small intestine)
receives secretions from the liver and pancreas
further digestion occurs
physical breakdown of food
slicing and chewing action of the teeth
increases surface area for enzyme action
continues with churning action caused by contraction of muscles in the stomach wall
chemical digestion of food
enzyme hydrolyse molecules into smaller soluble molecules
why are multiple enzymes needed for molecules to be chemically digested
enzymes are specific so more than one is needed to hydrolyse a large molecule
one enzyme will hydrolyse a large molecule into sections and then the other will hydrolyse these sections into their monomers
carbohydrases function
hydrolyse carbohydrates ultimately to monosaccharides
lipases function
hydrolyse lipids into glycerol and fatty acids
proteases function
hydrolyse proteins ultimately to amino acids
starch digestion
salivary glands secrete salivary amylase
amylase hydrolyses starch into maltose
duodenum has pancreatic juices which contains pancreatic amylase which hydrolyses starch
peristalsis moves food along the intestine membrane bound maltase
hydrolyses maltose into alpha glucose