Biology Topic 2 Flashcards
(464 cards)
what are lungs
an organ adapted for gas exchange
what is another word for breathing
ventilation
what are alveoli
the site of gas exchange
why do we as humans need lungs
larger and more complex organisms have a smaller surface area to volume ratio and low diffusion distance from skin to organs
how do smaller organisms perform gas exchange if not through lungs
through the skin
why can small organisms afford not to have lungs
they have a large surface area to volume ratio so they can rely on diffusion from the air to perform gas exchange through the skin
what is the movement of the ribcage during inhalation
up and out
what is the movement of the diaphragm during inhalation
contracts and moves down
what is the change in chest volume during inhalation
increase
what is the movement of the ribcage during exhalation
down and in
what is the movement of the diaphragm in exhalation
relaxes and moves up
what is the change in chest volume during exhalation
decreases
what proportion of CO2 is inhales
0.04%
what proportion nitrogen is inhaled
78%
what proportion oxygen is inhaled
21%
what proportion of O2 is exhaled
17%
what proportion Co2 is exhaled
4%
what proportion nitrogen is exhaled
78%
give 4 adaptions of the alveoli to diffusion
well ventilated
lots of them and they are folded
good blood supply
one cell thick cell wall
how does the alveoli being well ventilated help with diffusion
maintains steep concentration gradient
how does having lots of alveoli and them being folded help with diffusion
increases surface area over which diffusion can occur
what does a good blood supply do to help with diffusion in the alveoli
maintains steep concentration gradient
what does a one cell thick cell membrane in the alveoli do to help diffusion
short diffusion pathway enables more diffusion
can you label a diagram of the lungs?
well done!