physio nov 20

• external respiration is the diffusion of gases in lungs
• internal respiration is the diffusion of gases at body tissues

• diffusion of molecules between gas and liquid
• partial pressure gradients

total pressure exerted by mixture of gases=sum of pressures exerted by each gas

• decrease in P_o2 and increase in P_co2
• increase in water vapor and temperature

• amount of gas that dissolves in liquid depends on solubility (Co2 is more soluble than o2) and temperature (solubility decrease with increase in temperature)
• decrease in volume, increase in pressure, more gas dissolves in liquid

• Po2 of tissues, pH and temperature
• low Po2 and pH, and high temp increases O2 release

• 1.5% through solution in plasma
• 98.5% loosely bound to each Fe of hemoglobin (reversible reaction)

weaking of the Hb-O2 bond

• modify the structure of hemoglobin (decrease affinity for o2), enhance unloading
• occur in systemic capillaries 
• shift O2 hemoglobin dissociation curve to the right 

partial pressure is lower, so there is less of a pressure gradient: not as much O2 gets into blood, so need to breathe more to get the same amount of oxygen

• 7-10% dissolved in plasma
• 20% bound to globin of hemoglobin (amino acid-carbaminohemoglobin)
• 70% transported as bicarbonate ions in plasma

carbonic anhydrase

RBC to form carbonic acid which quickly dissociates to bicarbonate ions