Hemoglobin Structure and Function Flashcards
Ferrous iron is _____.
Fe2+
Ferric iron (Fe3+) cannot bind _____.
oxygen
Ferric iron in methemoglobin is reduced by ______.
cytochrome b5 reductase
What is P50?
P50 is the partial pressure value at which hemoglobin is half saturated.
Acidic solutions ____ the oxygen affinity of hemoglobin.
decrease
Increases in CO2 _____ the oxygen affinity of hemoglobin.
decrease
Temperature is _________ to the oxygen affinity of hemoglobin.
inversely proportional
2,3-BPG ______ the oxygen affinity of hemoglobin.
decreases
Alpha chains replace ______ chains.
zeta
Gamma chains replace ______ chains.
epsilon
Hemoglobin A2 functions like hemoglobin A. It is composed of ______.
alpha2/delta2
Heinz body anemia results from _____.
unstable hemoglobins precipitating in RBCs
Those with unstable hemoglobin disorders need ______.
folic acid (blood transfusions are usually unnecessary)
Disorders in which hemoglobin’s oxygen affinity is enhanced result in ____ RBC counts.
increased (because the Hgb doesn’t release O2 and the kidneys think the body is hypoxic)
Methemoglobinemia can be caused by _______, among other things.
cytochrome-b5 reductase deficiency, contaminated well water (with nitrates), and drugs such as benzocaine, sulfa, dapsone, and phenacetin
Methemoglobinemia can be treated with ______ (if metHgb levels are greater than 40%).
methylene blue
In addition to competitively binding at the O2 sites, CO also ____ shifts the oxygen binding curve, thus making it harder for hemoglobin to release O2.
left
High-affinity hemoglobins (such as Chesapeake hemoglobin) lead to ______.
erythrocytosis
Chronic methemoglobinemia requires ______ for treatment, but acute methemoglobinemia levels greater than _____ require ______.
nothing; 30%; methylene blue
Carboxyhemoglobin will give a falsely _____ pulse-ox reading.
high
Hemoglobin Koln is a mutation in the ____ chain that results in ______ affinity hemoglobin.
beta; increased
Hemoglobin Poole is a mutation in the _____ chain that results in _________ that resolves after birth.
gamma; infantile hemolytic anemia
List three causes of cyanosis.
Excess deoxyhemoglobinemia (many causes)
Excess methemoglobinemia
Sulfhemoglobinemia
Methemoglobin is _____ shifted.
left
Hemoglobin M is __________.
methemoglobin
CO poisoning _____ shifts the hemoglobin binding curve.
left
