Unit 5 - Hemoglobin Diseases Flashcards
Oxyhemoglobin
LOADS oxygen in lungs
What is the affinity for oxygen of oxyhemoglobin
High
What form is oxyhemoglobin in?
R or Relaxed form
Deoxyhemoglobin
UNLOADS oxygen in the tissues
Affinity for oxygen of deoxyhemoglobin
Low
What form is deoxyhemoglobin in?
T or tense form
What does 2,3 DPG do?
Changes oxyhemoglobin into deoxyhemoglobin
Where does 2,3DPG insert itself?
Between beta chains of molecule to make deoxyhemoglobin
What does 2,3DPG do to return hemoglobin into oxyhemoglobin?
Exits space between beta chains of molecule to make oxyhemoglobin
When 2,3DPG moves out of deoxyhemoglobin, what is this called?
Respiratory movement that makes hemoglobin act as diaphragm for oxygen
What does a shift to the right mean?
Right = Low Affinity, Release of oxygen
2,3DPG levels in a shift to the right
Increased levels
When does hemoglobin unload more oxygen to tissues?
In a shift to the right
At same given tissue partial pressure of oxygen
Conditions causing a shift to the right
Inc metabolism
Inc temperature
Dec pH
Tissue hypoxia
Inc carbon dioxide
What is a shift to the left?
Giving up less oxygen to the tissues
Won’t let go
If the body is under more restful conditions, what way will the curve shift?
To the left
When does hemoglobin unload LESS oxygen to the tissues?
In a shift to the left
At same given tissue partial pressure of oxygen
Conditions causing shift to the left
Dec metabolism
Inc pH
Inc abnormal hgb
Dec carbon dioxide
Bohr effect
Effect of pH on hgb-O2 affinity
More acidic = x affinity for oxygen
Less
More acidic = x shift of oxygen
Right
Acidic situations = x CO2
Increased
As hemoglobin unloads oxygen, what can it accept as a blood buffer?
Hydrogen ion
Chemical variant of hemoglobin definition
Hemoglobins with reduced or absent gaseous exchange capacity
Examples of chemical variants of hemoglobin
Carboxyhemoglobin
Methemoglobin
Sulfhemoglobin
Carboxyhemoglobin
Carbon monoxide replaces oxygen
Less binding sites for oxygen
How does CO bond to hgb compare to O2?
CO has a 200x tighter bond than oxygen
What color does carboxyhemoglobin produce to the RBC?
Cherry red color
What causes carboxyhemoglobin?
Smoking
Exhaust fumes from fuel bunring
Treatment for carboxyhemoglobin
Treatment with oxygen
What happens if carboxyhemoglobin is not treated?
Prolonged anoxia
Can be fatal or cause permanent damage
Methemoglobin
Chemically oxidized hgb from ferrous to ferric
Normally, what percentage of our hemoglobin is methemoglobin?
1%
What keeps our percentage of methemoglobin in check?
Methemoglobin reductase
What happens if methemoglobin becomes pathologic?
Cyanosis observed
What causes methemoglobin
Inherited enzyme deficiency
Hemoglobin M
Drugs or dyes
What does hemoglobin M do?
Mutation that stabilizes Fe+++ state
What drugs or dyes cause methemoglobin
Aniline dyes (ink, crayons)
Sulfonamides
Nitrates
Lidocaine
Treatment of methemoglobin
Methylene blue or ascorbic acid
Sulfhemoglobin
Permanent replacement of oxygen by sulfur
Causes of sulfhemoglobin
Sulfur containing cathartics
High levels of sulfonamide antibiotics
Can routine hemoglobin analysis measure sulfhemoglobin?
NO
What is the routine hemoglobin analysis
Cyanmethemoglobin
What can cyanmethemoglobin method not do?
Measure sulfhemoglobin
What are genetic varaints of amino acid sequence of globin chains
Hemoglobin S
Hemoglobin C
What are two ways RBCs are removed from circulation
Extravascular destruction
Intravascular destruction
Example of extravascular destruction
Macrophage removal in the spleen
Intravascular destruction example
Hemolysis
Three chemical components of hemoglobin
Heme
Iron
globin
When macrophage process RBCs, what components of hemoglobin are conserved?
Amino acids from globulins and Fe conserved for synthesis of new molecules
When RBCs are processed by macrophages, what happens to the heme?
Heme is converted into biliverdin
Biliverdin converted to bilirubin
Bilirubin released to blood for additional processing
Liver excretes bilirubin
Macrophage processing is what component of hemolysis?
Extravascular
Haptoglobin
CirculatingProtein in circulation that conserves free hemoglobin
What happens without haptoglobin?
Hgb can pass through the kidneys into urine
What happens to prevent hgb excretion?
Hgb-haptoglobin complex forms
Too big to be filtered
Liver cells take it up
What does the liver cells to to hemoglobin?
Processes hemoglobin similar to macrophages
What is a marker for IV hemolysis?
Decreased haptoglobin