Physiology Flashcards
what is Boyle’s law
At any constant temperature the pressure exerted by a gas varies inversely with the volume of the gas.
how is intra-pleural pressure affected by inspiration and expiration
Inspiration - falls
Expiration - rises
what is LaPlace’s Law
P=2T/r where P = inward directed collapsing pressure T = surface tension r = radius of the bubble
what is FVC and FEV1
forced vital capacity (max volume forcibly expelled from lungs following max inspiration)
forced expiratory volume in 1 sec
what is pulmonary ventilation
volume of air breathed in and out per minute
what is alveolar ventilation
volume of air exchanged between the atmosphere and alveoli per min
what is ventilation
the rate at which gas is passing through the lungs.
what is perfusion
the rate at which blood is passing through the lungs
what does V/Q measure
Ventilation compared to perfusion
what is the term for when alveoli well ventilated but not well perfused
alveolar dead space
what does decreased oxygen cause in the pulmonary and systemic arterioles
Pulmonary - vasoconstriction
Systemic - vasodilation
what does increased oxygen cause in the pulmonary and systemic arterioles
Pulmonary - vasodilation
Systemic - vasoconstriction
what is Dalton’s law of partial pressure
The total pressure exerted by a gaseous mixture = The sum of the partial pressures of each individual component in the gas mixture
what is partial pressure of a gas
pressure that one gas in a mixture of gases would exert if it were the only gas present in the whole volume occupied by the mixture at a given temperature
what is Fick’s Law of diffusion
The amount of gas that moves across a sheet of tissue in unit time is proportional to the area of
the sheet but inversely proportional to its thickness.
what is Henry’s Law
The amount of a given gas dissolve in a given type and volume of liquid (e.g. blood) at a constant temperature is proportional to the partial pressure of the gas in equilibrium with the liquid
what does Henry’s Law mean
that if the partial pressure in the gas phase is increased the concentration of the gas in the liquid phase would increase proportionally
what is the shape of the oxygen haemoglobin dissociation curve
Sigmoid curve
what is the shape of the myoglobin dissociation curve
hyperbolic
what is the Bohr effect
a shift of the sigmoid curve to the right
what is the Haldane effect
Removing oxygen from Hb increases the ability of Hb to pick-up carbon dioxide and carbon dioxide generated H+
what does the Bohr effect and the haldane effect work in synchrony to achieve
O2 liberation and uptake of CO2 & CO2 generated H+ at tissues
what is the ideal O2 stats for COPD patients
88-92%
what is the ideal O2 stats for patients
94-98%
what is the ideal O2 stats for patients
94-98%
how is oxygen transported in the blood
majority - bound to haemoglobin
small amount - in solution
