Gas Exchange Systems Flashcards
– are made up of gas exchange surfaces and the mechanisms that ventilate and perfuse those surfaces
gas exchange systems
cells need to obtain oxygen from the environment to produce an adequate supply of – by cellular respiration
ATP
CO2 is a – product of cellular respiration and it must be removed from the body to prevent toxic effects
end
- is the only means by which respiratory gases are exchanged between an animal’s internal body fluids and the outside medium
diffusion
the total number os gas molecules in a specified volume depends on –
pressure
atmospheric pressure at sea level is
760 mm of mercury
Because dry air is 20.9% O2, the – at sea level is 20.9% of 760 mm Hg or about 159 mm Hg
partial pressure of oxygen
the actual amount of gas in a liquid depends on the partial pressure of that gas in the gas phases in contact with the liquid as well as on the – of that gas in that liquid
solubility
the rate at which a gas such as oxygen diffuses between two locations
Q
D is the – which is a characteristic of the diffusing substance, the medium, and the temperature
diffusion coefficient
all substances diffuse faster at – temperatures and faster in air than in water
higher
cross-sectional area through which the gas is diffusing
A
P1 and P2 are the – of the gas at the two locations
partial pressures
the path length or distance between the two locations
L
(P1 -P2)/L is a
partial pressure gradient
Animals maximize D for respiratory gases by using – rather than – as their gas exchange medium
air rather than water
true or false: the slow diffusion of oxygen molecules in water affects both air-and water- breathing animals
true
oxygen content of air is much – than the oxygen content of an equal amount of water
higher
oxygen diffuses more – in air than in water
rapidly
animals has to do – to mover water or air over its gas exchange surfaces; more energy is required to move the denser water
work
fish need more oxygen when water is warmer but warm water carries – oxygen than cold water
less
– decreases with altitude
oxygen availability
the partial pressure of CO2 in the atmosphere is close to – both and sea level and atop Mount Everest
zero
getting rid of CO2 is not a problem for water breathing animals because CO2 is much more – in water than O2
soluble