Taylor- Hb, O2, CO2 Transport Flashcards
Discoloration of skin due to impaired O2 loading in the blood i.e. high deoxygenated Hb
cyanosis
Paleness in skin due to impaired blood perfusion i.e. low delivery of oxyHb (HbO2)
Pallor
2 main ways O2 is transported in the blood
- dissolved in plasma
- bound to Hb
main way O2 is transported
bound to Hb
P50=
PO2 at which Hb saturated w/ O2 is 50%
total O2 content in blood
Hb bound + dissolved
arterial or venous blood has higher O2 content
arterial
what drives O2 extraction in tissues
PO2 gradient
degree of O2 extraction depends on what
O2 demand of the organ (metabolic activity of tissue)
what 4 things cause Hb binding curve to shift down and to the right (O2 unloading)
increase H+ (low pH)
increase in PCO2
increase temp.
increase 2,3-BPG
what 4 things will cause Hb binding curve to shift up and to the left
decrease H+ (high pH)
decrease PCO2
decrease temp.
decrease 2,3-BPG
higher metabolic activity causes Hb binding curve to shift where
down and to the right
3 main ways CO2 is transported in the blood
- dissolved
- converted into H+ or HCO3-
- bound to Hb
main way CO2 is transported in the blood
as HCO3-
deoxygenated Hb can carry more CO2 than O2
Haldane Effect
in an environment where there is less O2 what happens
more CO2 is able to bind Hb
adult Hb
HbA (a2B2 subunits)
fetal Hb
HbF (a subunits)
when does HbF completely switch to HbA
by 6 months after birth
Hb binding curve for HbF
up and to the left of HbA
____ has higher O2 affinity than HbA
HbF
what promotes O2 release in fetal tissues
acidosis and metabolic activity
2 ways O2 transport is messed up
hypoxemia and impaired binding to Hb
low level of O2 in the blood
hypoxemia
unbound Hb by O2 is observable as
cyanosis
production of _____ increases where O2 availability is low
2,3-BPG
hypoxemia, anemia, heart failure are examples of what
where O2 availability is low
this is due to lower levels of Hb available therefore lower CaO2
anemia
this is due to higher levels of Hb available therefore higher CaO2
polycythemia
these 2 things affect CaO2, but NOT SaO2 (% saturation)
anemia and polycythemia
most heme contains what kind of iron
Fe2+
what happens when Fe2+ is oxidized to Fe3+
metHb forms that cannot bind to O2
will see cyanosis, normal PaO2, LOW SaO2
methemoglobinemia
to treat methemoglobinemia
methylene blue (reduces ferric iron Fe3+)
Hb has 200x higher affinity for ___ than O2
CO (carbon monoxide)
HbO2 binding curve shifts where when CO present
down and to the left
what causes CO poisoning
CO exposure
to treat CO poisoning
100% O2
this will have peripheral cyanosis, normal PaO2, LOW SaO2
CO poisoning
oxygen delivery (DO2)=
CO (cardiac output) x CaO2
In which individual would you predict low PaO2?
neither
In which individual is O2 delivery likely limited by local vasoconstriction?
B
In an anemic patient, which of the following would you expect to be low?
O2 content
In which of the following scenarios would you expect diminished arterial O2 content and cyanosis, but normal PaO2?
carbon monoxide poisoning
