HEMA Hgb Flashcards by Queenie Mae

HEMOGLOBIN

Structure
B. Biosynthesis
C. Regulation
D. Functions
E. Derivatives

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iron bearing protein contained
within the ___ .
it is synthesized by young
___ from the ____ up to _____.
____ can carry ___

Hemoglobin
-erythrocytes
-erythroblast
- polychromatophilic normoblast
stage
- reticulocytes stage
- one gram of hemoglobin
- 1.34 ml of oxygen

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1 heme= ___
1 hgb= ____

1mole of O
4 moles of 0

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FUNCTIONS OF
HEMOGLOBIN

Transport oxygen from the lungs
to the tissue and carbon dioxide
from the tissue.

Acid – base balance regulation
ph7.35-7.45

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Hemoglobin assist in maintaining the pH of blood by _____, ___ and ___ of ___ ( a regular vascular tone that refers to degree of constriction which blood vessel experience)

binding, releasing and transport of nitric oxide

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Structure of Heme
Composition of Heme

Protophorphyrin IX
Consists of a ring of :
Carbon ( C)
Hydrogen ( H)
Nitrogen
2.Ferrous iron (Fe2+)

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The______ comprising each hemoglobin molecule
consist of _____ , 141 to
146 amino acids each.
Each globin ___ separated by ___

Globin Structure
- four globin chains
-two identical pairs of unlike polypeptide chains
- 8 helices
-7 non helices segment

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Alpha
Beta
Gamma A
Gamma G
Delta
Epsilon
Zelta
Theta

Number of amino acids (important in each globin chain- * if not = problem esp. he,oglobinopathies)
141 (if Adult Hgb 141+ 141 alpha= 282 no more/less)
146
146 (position 136: alanine)
146 (position 136:glycine)
146
146
141
Unknown

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COMPLETE HEMOGLOBIN
MOLECULE
* The hemoglobin molecule can be described by its
1.
2.
3.
4.

COMPLETE HEMOGLOBIN
MOLECULE
1.primary, ——– amino acid sequence
2 Secondary —— helices and non
helices (pleated sheet)
3. Tertiary ——- pretzel like
configuration
4. quaternary ——- complete molecule

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Enzyme involved in Heme synthesis

ALA synthase (Aminolevulinic synthase)
ALA dehydralase
Hydroxymethylbilane synthase (PBG deaminase)
Uroporphyrinogen III synthase
Uroporphyrinogen III decarboxylase
Coproporphyrinogen-III oxidase
Protoporphyrinogen III oxidase
Ferrochelatase

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Flow of Heme synthesis

First step: Condensation- It takes place in mitochondria of Succinyl coA with Glycine w/c catalyzes by ALA synthase to form Amino levulinic acid. This ALA will go out from mitochondria which will go into cytoplasm, by the help of ALA dehydralase which will have multiple transformation/ reaction starting from Porphobilinogen-> hydroxymethylbilane which is catalyzed by Hydroxymethylbilane synthase (PBG deaminase). Then forming uroporphyrinogen III by the help of Uroporphyrinogen III synthase. Then will form COP3 (Coproporphyrinogen III) which will catalyzes by Uroporphyrinogen III decarboxylase, then it will go back to mitochondria to form Protoporphyrinogen III by the COP3 oxidase and eventually form Protoporphyrin IX by Protoporphyrinogen III oxidase.

Last step: In mitochondria, Insertion of Iron w/c will catalyzes by Ferrochelataseto form Heme.

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Always be ____ because if oxidize to ___ they can no longer bind to ___
- the oxidize hgb called ___ which can’t carry oxygen

Ferrous Iron (Fe2+)
Ferric
Oxygen
Methemoglobin

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Occurs in the cytoplasm of __ and
____.
* Polypepdtide chains are manufactured in the ___.
* ____ are made via transcription
of genetic code to mRNA and
translation of mRNA

SYNTHESIS OF GLOBIN
normoblast
reticulocytes
ribosomes
Globin protein

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ONTOGENY OF GLOBIN SYNTHESIS
Time Region
Type of Globin Gene
Type of Hb
1. 3 weeks of Gestation
2. 5 weeks of Gestation
3. 6-30 weeks of Gestation
4. 30 weeks of Gestation
5. At Birth

Yolk Sac
zeta and epsilon
Hb Gower1

Yolk Sac
γ&α
Hb Portland
Hb Gower II

Liver & spleen
α & γ & β
Hb F

Liver
delta
Hb A2

Bone marrow
___
HbA

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Hemoglobin Function

Oxygen Transport
Carbon dioxide transport
Nitric Oxide transport

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The function of hemoglobin is to readily bind oxygen molecules in the ___, which requires ____; ____; and_____, which requires low
oxygen affinity.

Oxygen Transport
lung
high oxygen affinity
to transport oxygen
to efficiently unload oxygen to the
tissues

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A second crucial function of
hemoglobin

Carbon dioxide transport

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third function of
hemoglobin involves the
___, ___ and ____. It is secreted by
vascular endothelial cells and causes relaxation of vascular wall smooth muscle and vasodilation .

Nitric Oxide transport
- binding, inactivation, and
transport of nitric oxide

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is the ability of hemoglobin to bind or release oxygen . Expressed in terms of the ___ at which hgb is 50% saturated

The relationship between ____ and ____ is described as ODC
_____ relationship of O2 affinity with Hb to pH which states that :
Inc pH ( alkalosis) = ______
Dec pH ( acidosis )= _____

OXYGEN DISSOCIATION CURVE
- Oxygen Affinity
- oxygen tension
- O2 tension(partial tension) and hemoglobin saturation with oxygen
-Bohr Effect
- Inc Hb affinity for O2
- dec hb affinity for O2

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FACTORS THAT INFLUENCE OXYGEN BINDING
Shift to the left Shift to the right
Temperature
Organic phosphates (2,3 DPG) 2,3-diphosphoglyceric acid
p(CO₂) partial pressure of carbon dioxide
p(CO)
pH

Decrease
Increase

Increase
Decrease

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HB-OXYGEN DISSOCIATION CURVE (Sigmoid curve)

the normal position of curve depends on __, ___, ____, ____

Concentration of 2,3-DPG
H+ ion concentration (pH)
CO2 in red blood cells
Structure of Hb

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Right shift (decreases oxygen affinity , more 02 release to the
tissues

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High 2,3-DPG
Dec body pH
High CO2
HbS

Left shift (increases oxygen affinity less 02 release to the
tissues

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Low 2,3-DPG
HbF
Dec body temperature

PHYSIOLOGIC FORMS OF
HEMOGLOBIN

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Oxyhemoglobin
Deoxyhemoglobin

hemoglobin in combination with oxygen. gives pinkness to the skin and mucous membrane. seen in ___

Oxyhemoglobin arterial circulation

hgb with iron but no O2 seen in ____ unassociated with oxygen __ formation

Deoxyhemoglobin venous circulation cyanosis (bluish nail)

NORMAL HEMOGLOBIN

1. Embryonic Hemoglobin a. Hgb Gower 1 b. Hgb Gower 2 c. Hgb Portland 2. Fetal Hemoglobin ( HbF) 3. Hemoglobin A or A1 4. Hemoglobin A2 5. Hemoglobin A3

Found in normal human embryos and fetuses with a gestational age of less than ___ Absent at birth

Embryonic Hemoglobin three months

Hgb Gower 1

Composed of 2 zeta and 2 epsilon globin chains

Hgb Gower 2

Composed of 2 alpha and 2 epsilon

Hgb Portland

composed of 2 zeta and 2 gamma

the major hemoglobin of the fetus and newborns Composed 0f ___ and ___ Produced ___

Fetal Hemoglobin ( HbF) 2 alpha and 2 gamma four months after conception

normal adult hemoglobin 95-97% of hemoglobin in normal adults produced after 1 yr onwards composed of __ and __

Hemoglobin A or A1 2 alpha (141 AA) and 2 beta chains(146 AA)

Constitutes less than 3% of the total hemoglobin Composed of ____

Hemoglobin A2 2 alpha and 2 delta

- degradation product of HbA2 - composed of ___ and ___

Hemoglobin A3 2 alpha and 2 delta

ABNORMAL HEMOGLOBIN

Hemoglobin S Hemoglobin C Hemoglobin E Hemoglobin H

This is the primary hemoglobin in people with ___ - have ____ and ___ causes the red blood cell to deform and assume a sickle shape when exposed to decreased amounts of oxygen. ____ is replaced by ____ in the 6th position of beta chain

Hemoglobin S (Sgaval) - sickle cell disease - two abnormal beta (βS) chains - two normal alpha (α) chains. Glutamic acid valine

About 2-3% of people of ___ descent are heterozygotes for hemoglobin C (have one copy of βC). seen in ___ - those with two copies of βC). instead of _____, ____ is in B6 It usually causes a minor amount of ____ and ____

Hemoglobin C (Cgal) -West African - homozygotes glutamic acid lysine hemolytic anemia mild to moderate enlargement of the spleen

is one of the most common beta chain hemoglobin variants in the world. * People who are homozygous of it (have two copies of βE) generally have a___, ____ and ____ * A single copy of it does not cause symptoms unless it is combined with another mutation, such as the one for ___

Hemoglobin E mild hemolytic anemia microcytic red blood cells mild enlargement of the spleen. beta thalassemia trait

an abnormal hemoglobin that occurs in some cases of ____ It is composed of ____ and is produced in response to a severe shortage of ___

Hemoglobin H - alpha thalassemia - four beta (β) globin chains - alpha (α) chains

Are acquired hemoglobin variants whose structure has been modified by drugs or environmental chemicals. do not transport oxygen to the tissue well resulting in __ and ___ . ___, __, and ___

CHEMICALLY MODIFIED HEMOGLOBINS - cyanosis (30%) and Coma and death (50%) a. methemoglobin b. sulfhemoglobin c. Carboxyhemoglobin

Is a form hgb in its ferric state * Has a ___ color and does not revert to red on exposure to oxygen. * Peak in the range of ___ at pH __under spectral absorption test. Causes : - ____ - ____

METHEMOGLOBIN ( HI) - brownish to bluish - 620 – 640 nm - 7.1 - Presence of oxidants - Genetic deficiency – decrease activity of MethHB

Formed by the irreversible oxidation of Hb of certain drugs and chemicals. examples : ___, ___ and ____ Formed by the addition of hydrogen sulfide to hgb has a _____. If it reaches the critical level in the blood it imparts ____-

SULFHEMOGLOBIN a. sulfonomides b. phenacetin c. acetanilide - greenish pigment - MAUVE LAVENDER

SULFHEMOGLOBIN Usually reported in the following situation 1. 2. 3. 4.

Usually reported in the following situation * 1. Px under prolonged treatment with sulfonamides or aromatic compounds ( phenacitin, acetanilide ) * 2. Px with severe constipation * 3. In cases of bacteremia caused by Clostridium perfringens * 4. In condition known as enterogenous cyanosis

Results from the binding of carbon monoxide to heme iron. * Hb can combine with carbon monoxide with affinity___ greater than that of Oxygen. * _____ is termed as silent killer for its colorless gas , odor and patient becomes easily ___.

CARBOXYHEMOGLOBIN - 200 times - Carbon monoxide -hypoxic

HEMOGLOBIN DETERMINATION

1. Visual Methods A. Sahli Method B .Dares Method c. Hadens Method D. Wintrobe E.Haldene F. Tallquists. 2. Gasometric Method 3. Spectronic Method A. oxyhemoglobin B. Cyanmethemolobin 4. Automated 5. Other Methods Alkaline Specific Gravity Comparato

quickest method

Tallquists

lyse RBC by mixing it with hypotonic sol'n

Haldene

Qualitative screening test based on specific gravity. The density of the drop of blood is ____ to the amount of hemoglobin it contains. The principle of the test is that 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 ___

Copper Sulfate Specific Gravity - directly proportional - 15 seconds

SG of 1.053= __

12.5g of Hgb

CuSO4 +Blood If blood floats = ____ If blood sink = ____

Inc Sg of CuSO4 > blood (dec hgb) Inc SG of Blood> CuSO4 (Inc Hgb= good to donate blood)

Principle: Hb will combine and liberate a fixed quantity of O₂. The blood is hemolyzed with ___ and the gas is collected and measured in a ___

Gasometric Method (Oxygen Capacity Method) - saponin - Van Slyke apparatus.

Colorimetric Methods A. Visual 1. 2. 3.

1. Direct Matching 2. Acid Hematin 3. Alkaline Hematin

Colorimetric Methods B. Photoelectric 1. 2.

Oxyhemoglobin method Cyanmethemoglobin or HiCN method

HEMA Hgb Flashcards

(54 cards)