PHYSIOLOGY OF HEMOGLOBIN

1. HEMOGLOBIN
PREPARED BY FATIMA SUNDUS

3. Four Hgb chains bind together loosely to form the entire
hemoglobin molecule. The different types of chains are
designated as
 alpha (α)
 beta (β)
 (γ) gamma
 (δ) delta chains.

4. • The synthesis of hemoglobin begins in the
proerythroblasts and continues even into the
reticulocyte stage of the RBCs.

5. ● Hemoglobin is the main protein in mature red blood
cells. Each RBC contains over 600 million hemoglobin
molecules. It is tetramer, that is, one molecule of
hemoglobin in adult is composed of four globin chains,
2 alpha and 2 beta. These chains are derived from
chromosome, mainly chromosome 16 and 11.

7. ● It carries oxygen from the lungs, where blood is
oxygenated, to body cells. When saturated with oxygen,
hemoglobin is called oxyhemoglobin

9. Carboxyhemoglobin
a compound formed in the blood by the binding of
carbon monoxide to hemoglobin. It is stable and
therefore cannot absorb or transport oxygen

11. Carbaminohemoglobin ( carbaminohaemoglobin BrE)
(CO2Hb), also known as carbhemoglobin and
carbohemoglobin) is a compound of hemoglobin and
carbon dioxide

13. in addition to oxygen and carbon dioxide, hemoglobin
takes up and releases a third gas, nitric oxide.
Nitric oxide plays an important role in regulating blood
pressure by relaxing the blood vessel walls, thus increasing
blood flow.

14. ● Hemoglobin is contained entirely in the red blood cells,
amounting to perhaps 35 percent of their weight.
● To combine properly with oxygen, red blood cells must
contain adequate hemoglobin.
● Hemoglobin, in turn, is dependent on iron for its formation.
● A deficiency of hemoglobin caused by a lack of iron in the
body leads to anemia.

15. ● Hemoglobin carries more than 20 times its volume of
oxygen. Some chemicals, such as carbon monoxide,
combine so firmly with hemoglobin that it can no longer
combine with oxygen.

18. ● After a life of perhaps 120 days, red blood cells are
destroyed in the spleen, or in the course of
circulation, their hemoglobin is broken into its
constituents, including iron, which enters new blood
cells formed in the bone marrow.

20. ● When blood vessels rupture, as in an injury, the red cells
are released and escape into tissue, where they are
broken down. The hemoglobin is converted into bile
pigments, the color of which is responsible for the
appearance of bruises.

22. ● Alterations in the structure of hemoglobin can lead to
life-threatening illnesses. The most important of these
conditions is sickle-cell anemia, which involves a
hereditary change in one of the amino acids that make
up hemoglobin. The thalassemia's are a group of
hereditary diseases of similar origin
● sickle cell anemia, the amino acid valine is substituted
for glutamic acid at one point in each of the two beta
chains. When this type of hemoglobin is exposed to low
oxygen, it forms elongated crystals inside the RBCs that
are sometimes 15 micrometers in length.)

25. ● Haemoglobin (Hb), protein constituting 1/3 of the red
blood cells
● Synthesis begins in proerythroblast
■ 65% at erythroblast stage
■ 35% at reticulocyte stage
● Two parts
■ Haem
■ Globin

26. ● Haem & globin produced at two different sites in the
cells
■Haem in mitochondria
■Globin in ribosome

27. HEMOGLOBIN FORMATION
the basic chemical steps in the formation of hemoglobin
 First, succinyl-CoA, which is formed in the Krebs metabolic
cycle binds with glycine to form a pyrrole molecule.
 In turn, four pyrroles combine to form protoporphyrin IX,
 which then combines with iron to form the heme molecule.
 Finally, each heme molecule combines with a long
polypeptide chain, a globin synthesized by ribosomes,
forming a subunit of hemoglobin called a hemoglobin
chain

29.  Each chain has a molecular weight of about 16,000; four
of these chains, in turn, bind together loosely to form the
whole hemoglobin molecule.

30. ● During the various stages of life such as embryonic, fetal and
adult stages, different globin chains are expressed. During the
fetal period, from about two months until birth, the dominant
globin chain is alpha and gamma and this is known as
fetal hemoglobin (HbF).
● However, shortly after birth about 3-6months, one will notice a
fall in fetal hemoglobin (HbF) and a there will be a rise in adult
hemoglobin (HbA). An alteration to the alpha or beta globin will
result in an abnormal hemoglobin.

31. FUNCTIONS
● The major role of hemoglobin is to carry oxygen from
the lungs to the tissues and return carbon dioxide (CO2)
from the tissue to the lungs. It is the oxygen carrying
component of RBCs. Oxygen binds to hemoglobin with
high affinity in an oxygen-rich environment and leaves
hemoglobin in an environment where there is not
enough oxygen.

32. Normal Range of Hb.
● For females the normal range for hemoglobin is : 11.5-
15.5 g/dl
● For males the normal range for hemoglobin is : 13.5-
17.5 g/dl

33. Conc of Hb in RBC
● RBCs can concentrate maximum Hb upto 34 gms per 100ML
Of Blood.
● OXYGEN BINDING POWER OF Hb:
MALE : 100 ml of Blood(16gm) can carry 21 ml of oxygen.
FEMALE : 100 ml of blood(14gms) can carry 19 ml of oxygen.

34. TYPES OF HAEMOGLOBIN
HbA ( Alpha2 Beta2)
HbA2 ( Alpha2 Delta2)
HbF ( Alpha2 Gamma2)
Gower I ( Zeta2 Epsilon 2)
Gower II (Alpha2 Epsilon2)