CHAPTER 4 Flashcards
HEMOGLOBIN
RBC
vit and minerals
35%
65%
Molecular weight:
64,000 Daltons
Respiratory pigment: gives the red color to the blood
HEMOGLOBIN
1 gm Hb can carry (?) O2
1gm Hb can carry (?) Fe
1.34 ml
3.47 mg
Represents (?) of the total body weight
> 1%
It occupies (?) of the red cell mass ([?]O2)
28%
72%
HB BIOSYNTHESIS Regulated by
oxygen tension in the kidneys
Hormones
Enzymes in the heme synthesis pathway
FUNCTION
Lungs –
Tissues –
100 mmHg
20 mmHg
– imp for gas exchange
Ca and CO2
COMPONENTS
Globin chain
Heme group
2, 3 BPG
Globin chains
2 Alpha Chains
2 Beta Chains
Dimer
Globin chain
Determines the type of Hb
Globin chain
The difference in the globin chain relates both to the
(?) in the chain.
sequence and to the number of amino acids
Heme =
Protoporphyrin IX + Fe+2
141
A
Z
Unknown
E
146
B
D
G
Portland
ZG
Gower 1
ZE
Gower 2
AE
HbF
AG
HbA1
AB
HbA2
AD
Occurs in the mitochondria and cytoplasm of bone marrow erythrocyte precursors
HEME SYNTHESIS
Organ for removing:
spleen + macrophages
STAGES
Iron is delivered to reticulocyte by transferrin
Iron Delivery and Supply
Inside the mitochondria
Synthesis of Protoporphyrins
Mediated by erythropoietin and vit B6
Synthesis of Protoporphyrins
Recycling
Hb Degradation
Separation of globin (transported) and heme (further processing)
Hb Degradation
Cellular respiration; alters O2 carrying capability
2, 3 DIPHOSPHOGLYCERATE (DPG)
90% of tot energy needed by rbcs
2, 3 DIPHOSPHOGLYCERATE (DPG)
Major pathway
2, 3 DIPHOSPHOGLYCERATE (DPG)
2, 3 DIPHOSPHOGLYCERATE (DPG) PATHWAY
Rapoport-Luebering Shunt
Regulates Hemoglobin affinity to O2
2, 3 DIPHOSPHOGLYCERATE (DPG)
Facilitate the unloading oxygen from Hb in the tissues
2, 3 DIPHOSPHOGLYCERATE (DPG)
Breakdown of the RBC (splenic culling, phagocytosis)
ERYTHROCYTE DESTRUCTION
Toward the end of 120 day life span of the RBC, it begins to break down.
ERYTHROCYTE DESTRUCTION
The membrane becomes
less flexible
The concentration of cellular hemoglobin
increases
Enzyme activity, especially glycolysis,
diminishes
Occurs when hb breaks down in the blood and free hb is released into plasma
Intravascular Hemolysis (10%)
Free hb binds to the haptoglobin, hemopexin and albumin and engulfed by macrophages.
Intravascular Hemolysis (10%)
Intravascular Hemolysis (10%) Laboratory:
o Increased plasma Hb
o Serum Bilirubin
o Serum Lactose
Dehydrogenase
o Decreased serum
haptoglobin
amino acids go back to the amino acid pool
GLOBIN
Fe & Protoporphyrin
HEME
: split off and removed by its attachment to a B-1- globulin
Iron
Iron - reused carried by
transferrin
Iron - stored
(ferritin or hemosiderin)
- broken at the alpha methene bridge by heme oxygenase
Protoporphyrin ring
- imp in the liver andspleen
Protoporphyrin ring
- biliverdin and CO
Protoporphyrin ring
NORMAL HEMOGLOBINS
EH
HbF
HbA1
HbA2
first 3 months after conception
Embryonic hemoglobins
= analogue of alpha chain
zeta chain
= counterpart of the
gamma, beta and delta chains.
epsilon chain
Major Hb of the fetus and the newborn infant
Hb F
Acid and alkali resistant
Hb F
Measured by
Alkali Denaturation & Kleihauer- Betke Acid Elution.
HbF %
After birth, smaller amounts of HbF are produced
- 6 months = HbF is less than
- After age 2 years = HbF less than
- Adults = less than
8%
2%
1%
HbA1 %
97%
HbA2 %
1.5 - 3.5%
HbA2
B-Thalassemias, hyperthyroidism and in some cases of megaloblastic anemia
Formed when the RBCs pass through the alveolar capillaries of the lungs.
Oxyhemoglobin (HbO,)
The O2 is loosely bound and unstable
Oxyhemoglobin (HbO,)
Scarlet red or bright red color
Oxyhemoglobin (HbO,)
Reduced form
Deoxyhemoglobin (HbCO2)
Dark red color
Deoxyhemoglobin (HbCO2)
The CO2 binds to the free amino group of the Hb to form
carbaminohemoglobin
Deoxyhemoglobin (HbCO2)
Cherry red color
Carboxyhemoglobin (HbCO)
Oxygen molecules bound to heme are replaced by carbon monoxide.
Carboxyhemoglobin (HbCO)
Chief Sources of CO:
automobile exhaust, industrial wastes, tobacco smoking, charcoal burning (10%)
CO Endogenous source:
< 1%
CO Critical Value:
5g /100 ml
May cause irreversible tissue changes
= asphyxiation
> 50 to 70%
(tissues deprived of O2)
asphyxiation
NaOH test:
40% NaOH + EDTA-blood
Warm gently
NaOH test
NaOH test
HbCO
HbCO2
Red (+) HbCO
Black-Brown (+)
Dilution test:
1mlblood+50mlwater
Dilution test:
HbCO
HbO2
Cherry Red, pink or bluish red
Yellowish red
Tannic Acid test:
1% Tannic acid
Tannic Acid test
HЬСО
HbO2
Red precipitate
Black-brown discoloration
Reduced iron (oxidized)
Methemoglobin/Hemiglobin (Hi)
Irreversible
Methemoglobin/Hemiglobin (Hi)
Iron in the hemoglobin molecule is in the ferric (Fe3) state instead of the ferrous (Fe2) state
Methemoglobin/Hemiglobin (Hi)
Incapable of combining with oxygen.
Methemoglobin/Hemiglobin (Hi)
Hi Normal
1.5%
Hi Daily
0.5% - 3%
- Cyanosis
1.5 g/dL (10%)
chocolate brown color
Hi
With strong affinity with CN
Hi
→ HiCN poisoning
(CN) + NO2 → Hi + CN
Carboxyhemoglobin (HbCO) Treatment:
administration of O2 (hyperbaric)
Carboxyhemoglobin (HbCO) Absorption wavelenght:
576 nm
Methemoglobin/Hemiglobin (Hi) Absorption wavelength:
630 - 635 nm
Most Iron in the body must be in
Ferrous state (Fe2+)
Binds to oxygen for transport to lungs and body tissues
Ferrous
is not able to bind hemoglobin but binds to transferrin
Ferric iron (Fe3+)
measures the amount of Fe3+ bound to Transferrin
Serum Iron
free iron; indirect
Serum Iron
total amount of iron that transferrin can bind when fully saturated
Total lron binding Capacity (TIBC)
Total lron binding Capacity (TIBC) causrd
dec iron consumption; improper recycling of Hb
indirect measurement of storage iron in tissue and bone marrow
Serum Ferritin
