Flashcards in 10. Hemoglobin modifications Deck (35):
hemoglobin modifications - types
hemoglobin modifications lead to
tissue hypoxia from decreased O2 saturation and decreased O2 content
hemoglobin - normal ron status
resuced state Fe2+
oxidized form of Hb ( ferric, Fe3+)
methemoglobin vs normal hemoglobin - iron status
normal : resuced state Fe2+ ( FERROUS)
methemoglobin : oxidized state Fe3+ ( FERRIC)
it does not bind O2 as readily
it has increased affinity for cyanide
methoglobinemia may present with
2. chocolate-colored blood
methoglobinemia can be treated with
1. methylene blue
2. vitamin C
how to treat cyanide ppoisoning ( and mechanism )
nitrites folloerd by thiosulfate
nitrites : hemoglobin --> methoglobin which bind cyanide
thiosulfate : to bind cyanide , forming thicocyanate, which renally excreted
methoglobinemia may be used
to treat cyanide poisoning
substance that cause poisoning by oxidizing F2+ to F3+ ( found in )
1. nitritrs ( from dietary intake or polluted / high altitude water)
Fe2+ to Fe3+
Fe2+ to Fe3+
methylene blue is used to
form of hemoglobin bound to CO in place of O2
CO binds to Hb in the place of ...
decreased oxygen binding capacity with left shift in oxygen hemoglobin dissociation curve
carboxyhemoglobin effect on curve
left shift in oxygen in oxygen - hemoglobin ( and decreased plateau)
carboxyhemoglobin causes in tissues
decreased O2 unloading in tissues
CO vs O2 on Hb
CO binds competitively to Hb and with 200x greater affinity than
100% O2 and hyperbaric O 2
how to treat methemoglobinemia
Changes to hemoglobin can lead to decreased O2 ____ and ____, causing hypoxia in tissues.
Normal Hb iron is ____(reduced/oxidized), or ____(ferric/ferrous). Methemoglobin iron is ____(reduced/oxidized), or ____(ferric/ferrous).
Reduced, ferrous (just the 2 of us: ferrous is Fe2+); oxidized, ferric (Fe3+)
• A man suffers from cyanide poisoning. What property of methemoglobin makes it useful for treatment?
The ferric (Fe3+) state of methemoglobin decreases the affinity for O2 but increases the affinity for cyanide
A cyanotic patient is found to have chocolate-colored blood. Treatment?
Methylene blue (this patient has methemoglobinemia)
A child has cyanide poisoning. What is the mechanism of action of nitrites used in the treatment?
Nitrites oxidize iron to form methemoglobin, which readily binds cyanide, restoring function to cytochrome oxidase
A patient has cyanide poisoning. What two treatments do you give?
Nitrites and subsequently thiosulfate
A patient looks blue and has blood that has turned brown. What caused this?
Poisoning by nitrites or benzocaine
What is the name of a form of hemoglobin in which carbon monoxide is bound instead of oxygen?
When another molecule, such as carbon monoxide, binds to hemoglobin in place of oxygen, what are the systemic effects?
CO causes a left shift in the oxygen-hemoglobin curve, resulting in tissue hypoxia from decreased oxygen unloading
Does carbon monoxide or oxygen have a greater affinity for hemoglobin?
CO has 200 times the affinity of oxygen for hemoglobin