Hemoglobin Flashcards by c k

in what form must iron be to bind oxygen?

reduced - ferrous

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what is hemoglobin with iron in ferric form called?

methemoglobin

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which enzyme reduces iron

cytochrome b5 reductase

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confirmation of deoxy hemoglobin?

taut (T)

due to salt bonds, hydrogen bonding, and hydrophobic interactions

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confirmation of oxy hemoglobin

relaxed - binding oxygen causes taut bonds to progressively break
(R)

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p50 of HbA at standard conditions

27mmHG

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2,3BPG is by-product of?

anaerobic glycolysis

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2,3BPG binds?

pocket between beta chains, stabilizing hgb in deoxygenated T state –> decreased O2 affinity –> right shift

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cardiac left to right shunt –> 2,3bpg?

increased 2,3 bpg –> right shift

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severe anemia –> 2,3bpg?

increase

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septic shock –> 2,3bpg?

decrease

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hpophophatemia –> 2,3bpg

decrease

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congestive heart failure –> 2,3bpg

increase

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bpg mutase deficiency –>

decrease in 2,3bpg

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hepatic cirrhosis –> 2,3bpg

increase

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transfusion of stored blood –> 2,3bpg

decrease

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severe acidosis –> 2,3bpg

decrease (because beyond bohr effect)

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methemoglobinema - curve shift?

left

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carbon monoxide poisoning - curve shift?

left

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fetal hemoglobin?

alpha2gamma2

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when does fetal hemoglobin dominate

after 8 weeks

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does Hgb F bind 2,3BPG better or worse than adult?

worse

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fetal curve relative to adult

left

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Hemoglobin A2

alpha2/delta2
2% adult
functions like HgbA except more heat stabile and slightly higher affinity for O2

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HgbA2 elvated in?

beta thalassemia sickle cell hyperthyroidism megaloblastic anemia

unstable hemoglobins have tendency to spontaenously denature often due to mutations that disrupt the stablility of?

the heme-globin linkage

untable hemoglobins may lead to

hemolytic anemia with jaundice and splenomegaly

unstable hemoglobins can be referred to as?

Heinz body anemia

hemoglobin koln

unstable one of the most common mutation in beta increased affinity (left)

hemoglobin poole

unstable hemoglobin gamma chain mutation infants with hemolytic anemia - which resulsove within a few months becasue you no longer make gamma

do unstable hemoglobins usually need blood transfusions?

unstable hemoglobin treatment

folic acid * splenectomy is not curative * may not see Heinz bodies until after splenectomy

Hemoglobin chesapake

high affinity | alpha globin chain

altered oxygen affinity hemoglobins and their stabilty

usually stable

altered oxygen affinity hemoglobins and electrophoresis

usually abnormal

altered oxygen affinity hemoglobins and hemolysis

usually none

high oxygen affinity variants and tissue oxygenation

leads to hypoxia --> leads to EPO production by kidney --> increased RBC count *generally no treatment need

low O2 affinity Hb anemia? presenation?

mild anemia | cyanosis

cyanosis most common cause?

deoxygenated hemoglobin - not necessarily hypoxia

differential dx | cyanosis and globins (3)

too much deoxy too much methemoglobin sulfhemoglobinemia

differential dx of cyanosis: | inadequate O2 of Hb (5)

``` pulmonary disorders cardiac right to left shunt congestive heart failur cardiovascular collapse (shock) low o2 affinity Hb variant ```

differenital methemoglobinemia (5)

``` congenital cytochrome b5 reductase deficiency cytochrome b5 deficiency M hemoglobins Acquired (drugs / toxins) ```

differential sulfemoglobinemia

acquired (drugs/toxins)

methemoglobinemia

Fe3+ cannot carry oxygen curve shifts left p50 goes down 1% is normal

color of methemoglobin

chocolate :)

congential methhemoglobinemia

cytochrome b5 reductase deficiency (autosomal recessive)

congential methemoglobinemia - clinical

increased o2 affinity blue and well at birth (will be blue but does not affect qol) up to 40% methemoglobin asymtpomatic heterozygotes unless oxidant expozed

hemoglobin M

autosomal dominant mutation in a or b chain making fe3+ resistant to reduction asymptomatic cyanosis normal amount of hemoglobin with mild hemolysis abnormal electrophoresis - M band

acquired methemoglobinemia | potential ways to aquire (2)

drugs | well water

acquired methemoglobinemia when and what to treat with?

if level is greater than 40% and there are symtpoms - give methylene blue (an artificial electron acceptor)

methemoglobin (acute vs chornic?)

acutely ill will yield problems - give methylene blue | chronic not so much

hemoglobin F | is it oxidized more or less readily to ferric state

Hemoglobin Flashcards

(61 cards)