10. Hemoglobin modifications Flashcards Preview

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Flashcards in 10. Hemoglobin modifications Deck (35):
1

hemoglobin modifications - types

1. methemoglobin
2. carboxyhemoglobin

2

hemoglobin modifications lead to

tissue hypoxia from decreased O2 saturation and decreased O2 content

3

hemoglobin - normal ron status

resuced state Fe2+
FERROUS

4

ferrous hemoglobin

Fe2+

5

ferric hemoglobin

fE3+

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Metheglobin

oxidized form of Hb ( ferric, Fe3+)

7

methemoglobin vs normal hemoglobin - iron status

normal : resuced state Fe2+ ( FERROUS)
methemoglobin : oxidized state Fe3+ ( FERRIC)

8

methemoglobin properties

it does not bind O2 as readily
it has increased affinity for cyanide

9

methoglobinemia may present with

1. cyanosis
2. chocolate-colored blood

10

methoglobinemia can be treated with

1. methylene blue
2. vitamin C

11

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

12

methoglobinemia may be used

to treat cyanide poisoning

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substance that cause poisoning by oxidizing F2+ to F3+ ( found in )

1. nitritrs ( from dietary intake or polluted / high altitude water)
2. benzocaine

14

benzocaine poisoning

Fe2+ to Fe3+

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nitrites poisoning

Fe2+ to Fe3+

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methylene blue is used to

treat methoglobinemia

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carboxyhemoglobin

form of hemoglobin bound to CO in place of O2

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CO binds to Hb in the place of ...

O2

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carboxyhemoglobin causes

decreased oxygen binding capacity with left shift in oxygen hemoglobin dissociation curve

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carboxyhemoglobin effect on curve

left shift in oxygen in oxygen - hemoglobin ( and decreased plateau)

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carboxyhemoglobin causes in tissues

decreased O2 unloading in tissues

22

CO vs O2 on Hb

CO binds competitively to Hb and with 200x greater affinity than

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carboxyhemoglobinemia
treatnebt

100% O2 and hyperbaric O 2

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how to treat methemoglobinemia

methylene blue

25

Changes to hemoglobin can lead to decreased O2 ____ and ____, causing hypoxia in tissues.

Saturation, content

26

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+)

27

• 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

28

A cyanotic patient is found to have chocolate-colored blood. Treatment?

Methylene blue (this patient has methemoglobinemia)

29

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

30

A patient has cyanide poisoning. What two treatments do you give?

Nitrites and subsequently thiosulfate

31

A patient looks blue and has blood that has turned brown. What caused this?

Poisoning by nitrites or benzocaine

32

What is the name of a form of hemoglobin in which carbon monoxide is bound instead of oxygen?

Carboxyhemoglobin

33

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

34

Does carbon monoxide or oxygen have a greater affinity for hemoglobin?

CO has 200 times the affinity of oxygen for hemoglobin

35

A man presents with a headache, nausea, and confusion. He was found in a small unventilated room with a space heater. Treatment?

100% O2 and hyperbaric O2 (this is likely carbon monoxide poisoning)