exchange Flashcards
(10 cards)
how does oxygen move into the blood
lungs into alveoli and dissolves in moist lining of alveolus. diffuses across alveolus epithelium and blood capillary epithelium. picked up by red blood cells
describe inspiration
diaphragm contracts external intercostal muscles contract ribs move up and out. pressure in the thorax decreases as volume increases causes air drawn into lungs. atmospheric pressure greater than pulmonary
describe expiration
diaphragm relaxes. external intercostal muscles contract ribs move down and in. volume of thorax decreases pressure increases forces air out of lungs. pulmonaryn press more than atm
adaptions of lungs for exchange
large sa to volume ratio
short diffusion pathway capillary walls very thin
partially permeable
conc gradient for diffusion
whats the formula for pulmonary ventilation
amount of air moved into the lungs in one minute
tidal volume x ventilation rate
how are fish adapted to efficient gas exchange
many lamella and filaments big sa
thin epithelium so distance gas has to travel is short. short diffusion pathway
describe counter current system
blood and water flow in opposite directions maintains conc gradient along the length of the filament as water is always next to blood with lower conc of o2
how are leaves adapted to gas exchange
leaves large sa as do air spaces between spongy mesophyll cells inside leaf
wind replaces air around the leaves to maintain conc gradient
many stomata means short diffusion pathway from most cells to the air
co2 moves into cells by diffusion through the stomata which are controlled by guard cells
describe the insect exchange system
large surface area to volume ratio
spiracles control the gas exchange and prevent too much water loss. happens mostly through simple diffusion. spiracles allow air to enter the tracheae
what do small organisms have
large sa to colume ratio. exchange occurs across the cell membrane surface for singke celled orgsnism
