Respiratory System 4 Flashcards
what are the two ways that oxygen is transported in the blood
dissolved in blood plasma and chemically bound to hemoglobin
define hemoglobin
protein contained in the red blood cells
how many molecules of oxygen can a molecule of hemoglobin carry
4, one on each heme
what is a fully saturated hemoglobin
all four heme groups bound to oxygen
what is a partially saturated hemoglobin
1,2, or 3 oxygen molecules are bound to a hemoglobin molecule
explain loading of O2 onto hemoglobin
occurs in the alveolar capillaries
oxygen binds to heme to form oxyhemoglobin (HbO2)
explain unloading of O2 from hemoglobin
occurs in the tissues
oxygens unbinds from hemoglobin to form deoxyhemoglobin and oxygen
what determines the direction of the hemoglobin reaction
partial pressure of oxygen in the blood and the affinity of hemoglobin and O2
define the cooperative binding effect
each O2 that binds causes a conformational change in hemoglobin making it easier for next O2 to bind
produces a sigmoidal (S-shaped) curve
explain the oxygen-hemoglobin saturation curve
initial curve is steep because of cooperative binding effect
as PO2 goes up, saturation goes up (happens in the alveoli)
as PO2 goes down, saturation goes down because it is being offloaded to go to the tissues
define oxygen reserve
oxygen bound to hemoglobin after passing through the systemic circulation
what are the 5 factors that affect hemoglobin’s binding and release of oxygen
PO2
pH
concentration of CO2
temperature
2,3-biphosphogylcerate (2,3-DPG)
explain how PO2 affects hemoglobin’s binding and release of oxygen
as PO2 goes up, we have more binding of O2 to hemoglobin
as PO2 goes down, we have more releasing of O2 from hemoglobin
explain how pH affects hemoglobin’s binding and release of oxygen
as pH goes down, H+ ions increase which decrease the affinity of oxygen to bind to hemoglobin
as pH goes up, H+ ions decrease which promotes the binding of oxygen to hemoglobin
explain how concentration of CO2 affects hemoglobin’s binding and release of oxygen
CO2 concentrations and saturation are inversely related
when CO2 concentrations increase, O2 is released from hemoglobin
when CO2 concentrations decrease, O2 is bound to hemoglobin