Diffusion and gas carriage in blood Flashcards
What is Daltons law
the pressure of a gas mixture is equal to the sum of the pressures of the individual gases
Composition of air in atmosphere
78.1% N, 20.9% O2, 0.033% CO2
what is the air in the lungs saturated by
they are fully saturated by water vapour
what is the diffusion barrier
a 2 cell thick blockade/barrier that oxygen and carbon dioxide pass through in gaseous exchange
what is Ficks law of diffusion
greater solubility for a particular gas means a greater rate of diffusion for that gas
partial pressure of gases in alveoli
PO2=105mmHg, PCO2=40mmHg
how much contribution does dissolved oxygen play
dissolved O2 could only supply muscles with 15ml/min at a cardiac output of 5l/min which is not enough
where does oxygen bind to
oxygen binds to one of four hemoglobin spots on each red blood cell
what does each Hb molecule contain
4 polypeptide chains and 4 haeme groups
what is a haeme group
a ferrous atom that binds to oxygen
how does Hb binding to O2 create a pressure gradient
the O2 that is bound to Hb does not contribute to the partial pressure of Oxygen in the blood
what shifts the oxyhaemoglobin dissociation curve
changes in temperature, effect of acidity, effect of CO2, effect of DPG concentration
what is DPG
a substance which helps release O2 into tissues
how is CO2 carried around body
23% binds to Hb, 70% carried as bicarbonate ions
