exchange - exam 2 Flashcards
features of a gas exchange surface
thin
large surface area
moist
contact w/ circulatory system (usually)
composed of living cells
what makes gills so good at respiration
high surface area directly in contact w/ water
ventilation mechanisms
one way flow
countercurrent exchanger
ventilation mechanisms of gills
flow of air over respiratory surface
countercurrent exchange
direction of water flow opposite the direction of blood flow
100% oxygenated water going down
0% oxygenated blood going up
blood picks up oxygen from the water because oxygen flows from high to low pressure
tracheal system
spiracles –> trachea –> tracheoles
why don’t insects need blood vessels
they use a tracheal system of respiration
brings outside environment close enough to nearly every cell to diffuse
lungs
nose –> trachea –> lungs –> bronchi –> bronchioles –> alveoli
alveoli
where gas exchange actually takes place
single layer of cells on the outside
surrounded by blood vessels
alveolus & capillary process
breathe in O2 rich air
O2 diffuses into the O2 depleted blood
CO2 diffuses into alveolus from CO2 rich blood
O2 rich blood circulates to body tissue
CO2 rich air exhaled
diaphragm & respiration
diaphragm contracts to increase volume of lungs
increase in volume = decrease in pressure
air gets pulled into the lungs
diaphragm relaxes
air gets pushed out of lungs
why is tidal gas exchange not entirely efficient
2 way air flow – deoxygenated air goes out the way it came in
mixing of fresh & dead air
gradient is not fully achieved
respiratory surface of birds
parabronchi
parabronchi
high surface area
1 way flow - through lungs
crosscurrent exchange - perpendicular
