lungs and diffusion Flashcards
diffusion
net random movement of molecules from an area of high concentration to an area of lower concetration
how does temperature affect diffusion rate
high temperature = higher kinetic energy so increased diffusion
how does concentration gradient affect diffusion rate
higher concentration gradient = more diffusion
how does distance affect diffusion rate
molecules have less distance to diffuse through so diffusion happens quicker
how does SA:V affect diffusion rate
larger SA:V ratio means faster diffusion
inhalation
diaphragm contracts
intercostal muscles contract
ribcage moves up and out
thorax volume increases
air pressure decreases
air pressure in thorax is less than atmospheric pressure
air rushes in
exhalation
diaphragm relaxes
intercostal muscles relax
rib cage moves down and in
thorax volume decreases
air pressure increases
air pressure in thorax is more than atmospheric
oxygen diffuses from where?
alveoli to red blood cells
carbon dioxide diffuses from where?
red blood cells to alveoli
why do the lungs have so many alveoli?
increased surface area
increased diffusion
why are the alveoli walls one cell thick
short diffusion distance
increased diffusion
trachea branches into what?
bronchi, bronchioles, alveoli
