Hemoglobin Flashcards
iron bearing protein contained
within the erythrocytes
hemoglobin
function of hemoglobin
Transport oxygen from the lungs
to the tissue and carbon dioxide
from the tissue.
it is synthesized by young
erythroblast from the
polychromatophilic normoblast
stage up to reticulocytes stage
hemoglobin
Composition of Heme
Protophorphyrin IX
Ferrous iron
amino acids of alpha and zeta
141
amino acids of beta
146
pretzel like
configuration
tertiary
amino acid sequence
primary
complete molecule
quarternary
helices and non
helices
secondary
Occurs in the cytoplasm of normoblast and
reticulocytes.
synthesis of globin
manufactured in
the ribosomes
Polypepdtide chains
made via transcription
of m genetic code to mRNA and
translation of mRNA.
Globin protein
the ability of hemoglobin to bind or
release oxygen . Expressed in terms of the oxygen
tension at which hgb is 50% saturated
oxygen affinity
The relationship between O2 tension and
hemoglobin saturation with oxygen is described as
OXYGEN DISSOCIATION
CURVE
relationship of O2 affinity with
Hb to pH
bohr effect
decreases oxygen affinity , more 02 release to the
tissues
right shift
increases oxygen affinity less 02 release to the
tissues
left shift
hemoglobin in combination with
oxygen.
gives pinkness to the skin and mucous membrane.
seen in arterial circulation
Oxyhemoglobin
hgb with iron but no O2 seen in
venous circulation
unassociated with oxygen
Deoxyhemoglobin
Found in normal human embryos
and fetuses with a gestational age
of less than three months
Absent at birth
Embryonic Hemoglobin
Composed of 2 zeta and 2 epsilon globin
chains
Hemoglobin Gower I
Composed of 2 alpha and 2 epsilon
Hemoglobin Gower 2
composed of 2 zeta and 2 gamma
Hemoglobin Portland
the major hemoglobin of the fetus
and newborns
Composed 0f 2 alpha and 2 gamma
Produced four months after
conception
Fetal Hemoglobin ( HbF)
normal adult hemoglobin
95 to 97 %of hemoglobin in normal
adults produced after one year
onwards
composed of 2 alpha (141 AA) and 2
beta chains(146 AA)
Hemoglobin A or A1
Constitutes less than 3% of the total
hemoglobin
Composed of 2 alpha and 2 delta
Hemoglobin A2
- degradation product of HbA2
- composed of 2 alpha and 2 delta
Hemoglobin A3
this is the primary hemoglobin
in people with sickle cell disease.
causes the red blood cell to deform and
assume a sickle shape when exposed to
decreased amounts of oxygen
Hemoglobin S
Glutamic acid is replaced by
valine in the
6th position of beta chain
It usually causes a minor amount of hemolytic
anemia and a mild to moderate
enlargement of the spleen
About 2-3% of people of West African
descent are heterozygotes for
hemoglobin C
is one of the most common beta
chain hemoglobin variants in the world
Hemoglobin E
an abnormal hemoglobin that occurs in some cases of
alpha thalassemia
hemoglobin H
Is a form hgb in its ferric state
* Has a brownish to bluish color and does not revert to
red on exposure to oxygen.
* Peak in the range of 620 – 640 nm at pH 7.1 under
spectral absorption test
METHEMOGLOBIN
Formed by the irreversible oxidation of Hb of certain drugs and
chemicals
Formed by the addition of hydrogen sulfide to hgb has a
greenish pigment.
SULFHEMOGLOBIN
If sulfhemoglobin reaches the critical level in the blood it
imparts
MAUVE LAVENDER
Results from the binding of carbon monoxide to heme
iron.
* Hb can combine with carbon monoxide with affinity
200 times greater than that of Oxygen.
CARBOXYHEMOGLOBIN
termed as silent killer for its
colorless gas , odor and patient becomes easily
hypoxic
Carbon monoxide.
qualitative screening test based on
specific gravity. The density of the
drop of blood is directly proportional to
the amount of hemoglobin it contains
Copper Sulfate Specific Gravity
Hb will combine and liberate a fixed quantity of
O₂. The blood is hemolyzed with saponin and
the gas is collected and measured in a Van
Slyke apparatus.
Gasometric Method (Oxygen Capacity
Method)
when
the drop of donor’s blood dropped into
copper sulfate solution becomes
encased in a sac of copper
proteinate, which prevents any
change in the specific gravity for
about 15 seconds
Copper Sulfate Specific Gravity
measures plasma hemoglobin
Oxyhemoglobin Method
Photoelectric
- Oxyhemoglobin Method
- Cyanmethemoglobin or HiCN
method
Colorimetric Methods
- Visual
- Photoelectric
Blood is diluted in a solution of potassium ferricyanide and
potassium cyanide. The hemoglobin is oxidized to
methemoglobin by the potassium ferricyanide.
Cyanmethemoglobin or HiCN
method
reagent used in hemoglobin determination
- pale and yellow with a pH of 7.2 +0.2
Modified drabkin’s reagent
Reference Range for cyanmethemoglobin
M: 13.5-18 g/dL
F: 12-15 g/dL
decreased hemoglobin
level
oligochromia
People living at high altitudes
increased Hb values
Excessive fluid intake
decrease hb
during
pregnancy
decrease hb
The panic Hb is less than 5.0 g/dl
a conditions that leads to
heart condition and death
A value more than 20 g/dl leads
to
clogging of the capillaries as a
result of hemoconcentration
