Physiology: ventilation perfusion & alveolar dead space Flashcards
what is meant by ventilation(V)
the rate at which gas is passing through the lungs
what is meant by perfusion(Q)
the rate at which blood is passing through the lungs
describe what is meant by the V/Q ratio
the ratio between ventilation and perfusion changes from top to bottom of the lungs, and can in pathology
what is alveolar dead space
ventilated alveoli that are not adequately perfused with blood are considered alveolar dead space
(very small + of little importance normally)
what is the physiological dead space
alveolar dead space + anatomical dead space
what can happen to alveolar dead space in disease
can increase significantly
what causes an increase in alveolar O2 conc.
increased ventilation
what causes the accumulation CO2 in alveoli
increased perfusion
what does increased ventilation lead to
pulmonary vasodilation which increases blood flow to match larger airflow
what does increased perfusion lead to
decreases airway resistance leading to increased airflow
in an area where perfusion(rate blood flow) is greater than ventilation(rate airflow) what will happen to CO2, O2, airflow, blood vessels, blood flow and airways
CO2 increases in area O2 decreases airflow increases local airways dilate blood flow decreases local blood vessels vasoconstrict
in an area where ventilation is greater than perfusion what will happen to CO2, O2, airflow, blood vessels, blood flow and airways
CO2 decreases in area O2 increases airflow decreases local airways constrict blood flow increases local blood vessels vasodilate