Digestive system Flashcards
What are enzymes
Enzymes are special protein molecule and they speed up reactions (e.g digestion)
why are enzymes needed for digestion
enzymes help break bonds that hold big insoluble molecules together
name the enzymes that break down:
~starch
~protein
~fat
~amylase
~protease or pepsin (only found in the stomach)
~lipase
why is digestion necessary
digestion is necessary so that it enables food molecules to enter our bloodstream as it breaks down large insoluble molecules into small soluble molecules that can be absorbed.
what happens in the mouth
mechanical and chemical digestion occur in the mouth. mechanical digestion is carried out by the teeth while chemical is carried out by enzymes in our saliva.
processes of digestion
1.ingestion - food is taken into the mouth
2.digestion - food is broken down into smaller molecules
3.absorption - where digested food is absorbed into the bloodstream
4.assimilation - where digested food is absorbed into the body cell
5.egestion - where food that cant be digested food goes out of the anus
what is peristalsis
peristalsis is a wave of muscular contractions to pass food down to the stomach
what are the two main parts of the small intestines and how long are they
Duodenum which is 10cm long
ileum which is 6 metres long
What are the adaptations of an ileum
~it is long
~folds
~villi
the benefits of the adaptations of the ileum
it increases the surface area for absorption
the adaptations of a villi
~good blood supply
~thin layer of surface cells on each villus
~permeable membrane
benefits of the adaptations of the villi
good blood supply - maintains a steep concentration gradient
thin layer if surface cells - short diffusion distance
permeable membrane - allows digested food molecules to pass through it easily
