gas exchange and gas transport in blood Flashcards
what is the rate of diffusion through tissues dependent on?
rate of diffusion through tissue water
what controls alveolar oxygen concentration?
rate of absorption by pulmonary capillaries and rate of oxygen entry into alveoli via ventilation
what effects the diffusion of gases through the respiratory membrane?
thickness of membrane, surface area of respiratory membrane, diffusion coefficient, pressure difference across the membrane
no gas exchange occurs is the Va/Q ratio is ______ or ______
zero or infinity
what two factors determine the PO2 and PCO2 in the alveoli?
how fast air comes in and the time to transfer across the membrane
why does CO2 diffuse more rapidly than O2?
CO2 is much more soluble, less pressure needed to cause CO2 diffusion than O2 diffusion
an increase in metabolism increases interstitial fluid ______ at all blood flow levels
PCO2
what carries 97% of O2 from lungs to tissues?
hemoglobin
about how many mL of O2 are left in tissue per 100 mL of of blood flow?
around 5
what factors shift the O2-hemoglobin dissociation curve to the right?
increase in blood acidity (lower pH), increase CO2, increased blood temperature, increased 2,3BPG, exercise
what factors shift the O2-hemoglobin dissociation curve to the left?
higher pH (more basic)
what does a shift to the right on the O2-hemoglobin dissociation curve indicate?
the hemoglobin has a lower affinity for oxygen
what does the Bohr effect do?
unloads O2 where it is needed most
why is carbon monoxide so dangerous?
it binds to the same site as oxygen on hemoglobin and can kill you
how can CO2 be transported from tissues to the lungs?
as CO2 in the plasma, combined with H2O in the RBC as carbonic acid (H+ and HCO3-)
