resp-5 gas properties Flashcards
what drives diffusion
different partial pressures
what is daltons law
total pressure is the sum of individual pressures (partial pressures)
what ranges is oxygen Po2
150-160mmHg
21%
ficks law of diffusion–> proportionalities
diffusion is proportional to area, diffusion constant, (P1-p2) and inverse to thickness
what is the diffusion constant
the amount of gas transferred between the alveoli and the blood/unit time
what is the diffusion constant proportional to
gas solubility
does co2 or o2 have a higher diffusion constant
co2
more soluble, same molecular weight
what entails diffusion constant
proportional to solubility, inversely proportional to molecular weight
henrys law
the amount of gas dissolved in a liquid is directly proportional to the partial pressure of gas in which the liquid is in equilibrium
what determines concentration of a gas in liquid (2 factors)
their solubility and their partial pressure
why is Po2 in air> po2 in alveoli
humidification of air in resp (more water, relative percentage of other molecules decreases)
loss O2 to blood diffusion (hemoglobin)
mixing inspired air with alveolar air (functional residual capacity)
what determines alveolar po2 and pco2
Po2 and PCO2 in atm
alveolar ventilation
metabolic rate (more you use, more you take)
perfusion
increasing alveolar ventilation does what do alveolar po2 and pco2
increase alveolar po2 and decrease alveolar pco2
increasing metabolic rate does what do alveolar po2 and pco2
decrease alveolar po2 and increase alveolar pco2
what determines arterial levels of gases
partial pressure of gas in alveoli
when does getting the first bit of o2 happen (in healthy person)
in the first third of the capillary system
what is cardiac output
volume of blood pumped by the heart per minute
does systemic or pulmonary system have higher pressure
systemic higher pressure
why is pulmonary low pressure system
only pumps blood to top of lung, shorter and wider vessels
why is the pulmonary high compliance vessels
lots of arterioles with low restine tone
thin walls and little smooth muscle can accept large amount of blood
can dilate in increase to pressure
when would alveolar capillaries collaps
if capillary pressure falls below
alveolar pressure, the capillaries close off, diverting blood to other pulmonary
capillary beds with higher pressures
what is the ventilation/perfusion ratio (V/Q0
balance
between LUNG ventilation (O2 ATM→ALVEOLI / CO2
ALVEOLI→ATM) and LUNG perfusion (O2 ALVEOLI → BLOOD
/CO2 BLOOD → ALVEOLI).
what is a major factor that the ventilation/pefusion ratio affects
the alveolar and arterial elvels of Po2 and Pco2
more ventilation does what to po2 and pco2
more closely alveolar po2 and pco2 will approach their respective valuesof the insipired air
