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Immunology > Hemoglobin > Flashcards

Flashcards in Hemoglobin Deck (28)
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1
Q

Hemoglobin is a ____mer

A

tetramer

2
Q

Heme =

A

proto + Fe

3
Q

Allosteric regulation

A

once a site is bound, affect affinity of another site to bind

4
Q

positive cooperativity

A

binding to O2 - increase affinity for O2

5
Q

Taut configuration

A

T - inter/intrasalt bonds - O2 concentration is low, 0/4 sites occupied

6
Q

R configuration

A

an oxygen binds ato a site, hgb changes to increase affinity for O2

7
Q

Oxygen dissociation curve - describe and explain

A

sigmoidal; due to positive cooperativity (myoglobin is hyperbola - monomer)

8
Q

P50

A

partial pressure at which 50% oxygen saturated

9
Q

pH decrease - shift

A

right - bonds O2 less tightly

10
Q

oxygen dissociation curve - axis and shift significance

A

y = O2 sat; X = partial pressure; Right = binds O2 less; Left shift = increase affinity - binds tigheter

11
Q

Temperature increase … shift?

A

right

12
Q

2,3 BPG increase - shift

A

right (2,3 BPG byproduct of anaerobic glycolytic pathway)

BPG increase = increased O2 utilization, glycolysis, chronic hypoxia, chronic anemia

13
Q

Embryonic hgb

A

hgb gower 1, grower 2, portland

14
Q

Fetal Hgb

A

alpha 2 gamma 2 - binds 2,3BPG poorly –> R state = increase affinity for O2

15
Q

Adult Hgb

A

A2B2

16
Q

HbA2 elevated= suggests?

A

beta thal, sickle cell trait/disease, hyperthryoidism, megaloblastic anemia

17
Q

Hemoglobin structural differences explanation

A

taut/relaxed configuration - inter/intra salt bonds within molecules
Once O2 binds -> R state -> easier to bind others

18
Q

Phsyiological effect of altered O2 affinity

A

allows O2 to be released in low pO2 (tissue) and O2 picked up in high pO2 (lungs)

19
Q

What is methemoglobinemia?

A

Fe3+ state in hemoglobin

20
Q

Biology of methemoglobinemia formation

A

reduced ability to convert Fe3+ to Fe2+ (ferric to ferrous) via NADPH reductace pathway

21
Q

Methemoglobinemia etiology

A

Acquired: Drugs, free radicals, H2O2, HNO3, OH-, CYP B5 decreases
Genetic: homogenous deficiency of cytochrome B5 reductase - humtantion in hemoglobin -> Hgb M (alpha/beta chain defect - inhibition of reduction of Fe3)

22
Q

Diagnose methemoglobinemia

A

cyanotic, but arterial pO2 normal on ABG; dark blood even with O2 exposure

23
Q

Treatment of methemoglobinemia

A

methylene blue/ascorbic acid, remove cause (if any)

24
Q

CO poisoning

A

CO binds 240x stronger –> carboxyhemoglobin –> allosteric change –> increase O2 affinity for hem = decrease O2 delievery to tissue

25
Q

CO poison treatment

A

Hyperbaric oxygen, 100% oxygen to compete CO binding site

26
Q

CO poison diagnosis

A

Co-oximetry

pulse-OX will NOT work!

27
Q

CO posion diagnosis

A

headache, malaise, nausea, seizure, coma, mycardial infarction, loss of cognition, personality change, movement disorder

28
Q

Pulse Oximeter - how does it work?

A

2 diodes emit 660 and 940 nm; deoxyhemoglobin max at 660, oxyhemoglobin at 940; comapre differences
inaccurate - nail polish, high motion, dark skin, anemia, shock, abnormal hemmorrhage,