topic 1 cell biology Flashcards
where does gas exchange occur
in the lungs
what is the job of the lungs
to transfer oxygen to the blood and to remove waste carbon dioxide from it
what do the lungs contain where gas exchange occurs
alveoli
what are alveoli
air sacks found in lungs- this is where diffusion of gasses occurs
what are alveoli specialised to do
maximise the diffusion of carbon dioxide and oxygen
give 4 features of alveoli
-extensive blood supply
-very thin walls
-a moist lining for dissolving gases
enormous surface area
what is the small intestine covered with
villi
what do villi do in the small intestine
they increase the surface area in a big way so that digested food is absorbed much more quickly into the blood
give 2 features of villi
- they have a single layer of surface cells
- a very good blood supply to assist good absorption
what is the size of the stomata controlled by
guard cells
what is the gas exchange for fish
gills
what is each gill made up of in fish
gill filaments
what do gill filaments do
give the gill a big surface area for exchange of gasses
what are the gill filaments covered up in
lamellae
what do the lamellae contain
- they have lots of blood capillaries to speed up diffusion
- they have a thin layer of cells to minimise the distance that gasses have to diffuse
