Lecture 25 - Hb, O2 transport and dissociation Flashcards
oxygen move from ____ to ____
alveoli; pulmonary capillaries
oxygen is carried in the blood in what 2 forms
- dissolved
- bound to hemoglobin
define hemoglobin
an iron-based, 4 protein chain in RBCs
T/F: adult and fetal hb have different protein chains
TRUE
what is the normal concentration of hemoglobin in blood
15 mg/dL
oxygen binds ____ with hemoglobin
reversibly
where does oxygen on-load and off-load?
on = lungs
off = tissue
hemoglobin binding is ____ and ____.
cooperative and saturable
why is the oxygen dissociation curve sigmoidally shaped
due to the cooperativity
what 4 physiologic states with shift the oxygen dissociation curve
- pH
- temperature
- CO2
- 2,3 DPG
describe a right shift to the oxygen curve
less saturation of Hb at any pO2 and more offloading of oxygen
describe the 4 physiologic states that will cause a right shift
- decreased pH (increased H+)
- increased PCO2
- increased temperature
- increased 2,3-DPG
where is right shift normal
in tissues
describe a left shift to the oxygen curve
increased saturation of Hb at given pO2 and less offloading of oxygen
describe the 4 physiologic states that will cause a left shift
- increased pH (decreased H+)
- decreased PCO2
- decreased temperature
- decreased concentration of 2,3-DPG
where is the left shift normal
the lungs
T/F: adult Hb is left-shifted compared to fetal
FALSE
define the Bohr effect
hemoglobin’s oxygen binding affinity is inversely related to both acidity and concentration of carbon dioxide
what enzyme is present in RBCs and used to maintain the carbonic acid equilibrium
carbonic anhydrase
most CO2 becomes what
bicarbonate
Give the equation for total oxygen content
CaO2 = sum of (Hb-O2) + (Dis-O2)
oxygen delivery (DO2) is equal to
cardiac output x CaO2
what 3 things negatively affect oxygen delivery
- decreased Hb levels
- decreased PaO2 (hypoxemia)
- decreased cardiac output
T/F: CO2 is continuously produced by aerobic metabolism
TRUE
