cardio 3.2 Flashcards
in what two forms is oxygen carried in the blood?
- dissolved in plasma (about 1.5%)
- bound to hemoglobin (most important, about 98.5%)
by how much does hemoglobin increase the O2 carrting capacity of blood?
by 70%
what binds O2 in Hemoglobin?
Fe+2
what does each hemoglobin sub-unit conatin?
a Heme Moiety
Hemoglobin is also known by what other name?
alpha2beta2
how saturated is hemoglobin in the arteries? (at a Po2 of 100mmHg)
98-100% saturated
how saturated is Hemoglobin a Po2 of 40mmHg? (e.g. mixed venous blood)
about 75% saturated
at what pressure is hemoglobin 50% saturated?
25mmHg (called P50) two of the four heme groups contains an oxygen
what is the change of hemogobins affinity for oxygen called?
positive cooperativity this change in affinity facilitates the loading of O2 in the lungs and unloading of O2 at the tissues (steep portion of the curve)
what four things influence the saturation of hemoglobin at a given Po2?
- Temperature
- Blood pH
- amound of 2,3-bisphosphoglycerate
- P(CO2)
where is 2,3-BPG produced ?
in glycolosis as RBC break down glucose
what causes shifts to the right on the dissociation curve? (decreased affinity for oxygent?
increases of:
P(CO2)
temperature
2,3-DPG
decrease of
pHwhat is the bohr effect?
increases in P(CO2) of a decrease in pH shifting the dissociation curve to the right
how does 2,3-DPG cause a shift to the right in the dissociation curve?
Binds to beta chains
what happens to 2,3-DPG at high altitudes?
increased synthesis facilitates the unloading of O2 at the tissues
what occurs when the dissociation curve shifts to the left?
- affinity for O2 is increased
- P50 is decreased (more dificult to unload O2 in tissue
- at any level saturation of hemoglobin is increased
how much greater is Hemoglobins affinity for CO2 then O2?
200X
does binding CO2 increase of decrease the affinity of hemoglobin for O2?
Increases the affinity
Contrast hypoxemia vs hypoxia
Hypoxemia decrease in Arterial P(O2)
Hypoxia Decrease in O2 delivery to the tissues
what are three causes of hypoxia?
- decreased cardiac output
- decreased O2 binding capacity of hemoglobin
- decreased arterial P(O2)
what is Anemic hypoxia?
poor O2 delivery resulting from too few RBCs or from RBC that contain abnormal or too little Hb
Ischemic (stagnant) hypoxia?
occcurs when blood circulation is impared (systemic of local)
what is histotoxic hypoxia?
when the body cells are unable to use O2 even though adequate amounts are delivered (poisons)
list hypoxemic hypoxia causes and indicator
indicated by reduced arterial P(O2)
abnormal ventalation-perfusion coupling
pulmonary diseases
breathing are with low O2
