Lesson 1 Flashcards
(42 cards)
Life saving substance of every red blood cell
The oxygen-carrying component of the RBC
Each RBC is nothing more than a fluid-filled
sac with the fluid being hemoglobin
Also spelled as haemoglobin, iron containing
protein in the blood pof many animals- in the
RBC (erythrocytes) of vertebrates- that
transport oxygen to the tissues.
Hemoglobin forms an unstable reversible bond
with oxygen
In the oxygenated state, it is called
oxyhemoglobin and is bright red; in the
reduced state, it is purplish blue
When red cell die, hemoglobin is broken up:
iron is salvaged, transported to the bone
marrow by proteins called transferrins, and
used again in the production of new RBC
The remainder of the hemoglobin forms the
basis of bilirubin, a chemical that is excreted
into the bile and gives the feces their
characteristics yellow-brown colour.
HEMOGLOBIN
- this portions involves the four iron
atoms in the ferrous state (Fe2+) - iron in the ferric state (Fe3+) cannot
bind oxygen - surrounded by protophorphyrin IX or
the phorphyrin ring, a structure formed in
the nucleated RBC- Protophorphyrin is the final product in
the synthesis of the heme molecule.
- Protophorphyrin is the final product in
Heme
-this structure consists of amino acids
linked together to form a
polypeptide chain, a bracelet of
amino acids.
-the most predominant chains for
adult hemoglobins are the alpha
and beta chains
- Alpha chains have 141 amino acids in
a unique arrangement, and beta
chains have 146 amino acids in a
unique arrangement.
Globin
Oxygen delivery
Capable of pulling CO2 away from the tissues
and keeping the blood in a balanced pH.
Function of Globin
Conjugated protein that serves as the vehicle
for the transportation of oxygen and carbon
dioxide.
When fully saturated, each gram of
hemoglobin holds 1.34 ml of oxygen
The red cell mass of adult contains
approximately 600g of hemoglobin, capable of
carrying 800 ml of oxygen.
HEMOGLOBIN STRUCTURE
- Hb A is the major (96-98%) normal adult
hemoglobin. - Hb F is the major hemoglobin of the fetus
and the newborn infant. Only traces of Hb
F (<1.0%) are found in adults. - Hb A2 account for 1.5% to 3.5% of normal
adult hemoglobin.
TYPES OF HEMOGLOBIN
is the major (96-98%) normal adult
hemoglobin.
Hb A
is the major hemoglobin of the fetus
and the newborn infant. Only traces of Hb
F (<1.0%) are found in adults.
Hb F
account for 1.5% to 3.5% of normal
adult hemoglobin.
Hb A2
Increasing the amount of any of these
abnormal hemoglobins in the bloodstream can
be potentially fatal.
The production of abnormal hemoglobins
results from accidental or purposeful ingestion
of absorption of substances, drugs that are
harmful.
Abnormal hemoglobins sometimes are
produced as a result of inherited defects.
ABNORMAL HEMOGLOBINS
- iron has been oxidized to the Ferric
state (Fe3+)- builds up in the circulation, if the
level is greater than 10%, individualsappear
cyanotic (blue color), especially fingers
and lips - aniline drugs and anti- malarial
treatments may induce a
methemoglobinemia.
- builds up in the circulation, if the
Methemoglobin
- hemoglobin with an affinity to
carbon monoxide (CO) that is 200 times
greater than its affinity for oxygen- therefore no oxygen is delivered
to the tissues - levels increases in smokers
and certain industrial workers - carbon monoxide poisoning.
- therefore no oxygen is delivered
Carboxyhemoglobin
agents such as sulfonamides or sulfa-
containing drugs.
- the affinity of sulfhemoglobin for
oxygen is 100 times lower than that of
normal hemoglobin.
- it may be toxic at a very low
level
Sulfhemoglobin
- medical terms for a group of blood
disorders and diseases that affect RBC- genetic defect that results in
abnormal structure in one of the
globin chains of hemoglobin
molecule.
- genetic defect that results in
Hemoglobinopathies
Common hemoglobinopathies is sickle cell and
thalassemia
May cause anemia inherited
Hemoglobin produced by genes that control
the expression of hemoglobin protein
Abnormal hemoglobin appear in one of the
three basic circumstances:
Hemoglobinopathies
Abnormal hemoglobin appear in one of the
three basic circumstances:
Structural defects in the hemoglobin
molecule
Diminished production of one of
the two subunits of the
hemoglobin molecule
Abnormal associations of otherwise
normal subunits
- alterations in the gene for one of
the two hemoglobin subunits
chains, alpha or beta, called
mutations- alteration of a single amino
acids disturbs the behavior of the
hemoglobin molecule, and
produces disease
state. - sickle hemoglobin exemplifies
this phenomenon
- alteration of a single amino
Structural defects in the hemoglobin
molecule
-Equal numbers of hemoglobin
alpha and beta chains are
necessary for normal function
-Hemoglobin chain imbalance
damages and destroys red
cells thereby producing anemia.
Diminished production of one of
the two subunits of the
hemoglobin molecule
-Beta globin subunits begin to
associate into groups of four
due to paucity of potential alpha
chain partners.
-These tetramers of beta globin
subunits are functionally
inactive and do not
transport oxygen.
Abnormal associations of otherwise
normal subunits
- A predominant hemoglobin in people
with sickle cell disease - alpha chain is normal
-disease producing mutation exist in beta
chain - if one single mutant gene and one
normal beta gene,sickle cell trait is
benign
Hemoglobin S
- results from a mutation in the beta globin
gene
-Hemoglobin C disease is relatively
benign, producing mild hemolytic
anemia and splenomegaly.
Hemoglobin C
- results from the mutation in the
hemoglobin beta chain manifest mild
hemolytic anemia and mild
splenomegaly.
Hemoglobin E
- tetramer composed of four beta
globin chains
-occurs only with extreme limitation of
alpha chain availability
Hemoglobin H
- variant in which the mutation in the
alpha globin gene produces an alpha
globin chain that is abnormally long.
Hemoglobin Constant Spring
