Transcript blood

BY
Dr shamshad Begum .A.Loni
Lecture notes
Composition
of Blood
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Constituents of blood
Formed elements 45%
Plasma 55%
RBCs
5 million/cumm (µl)
91.5% water
7% gm% proteins
3.8gm % albumin (54%)
2.7gm%
globulin (38%)
0.5gm % fibrinogen (7%)
1.5%
Electrolytes
Nutrients
Gases
Regulatory substances
Waste products
WBCs 10,000/cumm (µl)
neutrophils
60-70%
Eosinophils
2-4%
monocytes
3-8%
lymphocytes 25-30%
basophils
1%
Platelets 140-400000/µl
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Constituents of blood
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Thicker than water with a Specific gravity
around 1.58
pH 7.35-7.45
Colour: bright red when oxygenated
dark red when de-oxygenated
8% body weight
20% of ECF
Volume about 5 liters(70 ml/Kg body wt.)
Sampling by venipuncture; finger pick/heel
prick
arterial puncture
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Functions of blood
1. Transportation of
respiratory gases (O2 & CO2);
nutrients ; hormones;
waste products
2. Regulatory: body temperature; pH
3. Protection
against disease (immune functions);
against blood loss (coagulation)
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Erythrocytes are dedicated to respiratory
gas transport
Hemoglobin reversibly binds with oxygen
and most oxygen in the blood is bound
to hemoglobin
Composition of hemoglobin
◦ A protein called globin
 made up of two alpha and two beta chains
◦ A heme molecule
 Each heme group bears an atom of iron, which can
bind to one oxygen molecule
 Each hemoglobin molecule thus can transport four
molecules of oxygen
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Neutrophils are our body’s bacteria slayers
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Protect the body from infectious microorganisms
Can leave capillaries via diapedesis
Move through tissue spaces (amoeboid motion)
Many are phagocytic (possess numerous
lysosomes)
Leukocytosis – WBC count over 11,000/mm3
◦ Normal response to bacterial or viral invasion
Leucopenia - a decrease in WBC count below
4,800/mm3
Leukemia - a cancer of WBC
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Eosinophils account for 1–4% of WBCs
◦ Have red-staining, bilobed nuclei
◦ Have red to crimson granules
◦ Function:
 Lead the body’s counterattack against parasitic
infections
 Lessen the severity of allergies by phagocytosing
immune complexes (ending allergic reactions)
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Account for 0.5-1% of all WBCs
◦ Have U- or S-shaped nuclei with two or three
conspicuous constrictions
◦ Are functionally similar to mast cells
◦ Have large, purplish-black (basophilic) granules
that contain histamine
 Histamine – inflammatory chemical that acts as a
vasodilator and attracts other WBCs (antihistamines
counter this effect)
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Account for 20-25% or more of WBCs
and:
◦ Have large, dark-purple, circular nuclei with a
thin rim of blue cytoplasm
◦ Are found mostly enmeshed in lymphoid
tissue (some circulate in the blood)
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Most important cells of the immune
system
There are two types of lymphocytes: T
cells and B cells
◦ T cells - attack foreign cells directly
◦ B cells give rise to plasma cells, which produce
antibodies
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Monocytes account for 3–7% of leukocytes
◦ They are the largest leukocytes
◦ They have purple-staining, U- or kidney-shaped
nuclei
◦ They leave the circulation, enter tissue, and
differentiate into macrophages
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Platelets are fragments of megakaryocytes
Their granules contain serotonin, Ca2+,
enzymes, ADP, and platelet-derived
growth factor (PDGF)
Platelets function in the clotting
mechanism by forming a temporary plug
that helps seal breaks in blood vessels
Platelets not involved in clotting are kept
inactive by Nitric Oxide (NO) and
prostaglandins
Red Blood Cells (erythrocytes)
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No. 4-5 million/cumm (μL)
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Size 7μ, bi-concave discs
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No nucleus: can not reproduce = More
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surface area & center becomes thinner
(biconcave):
- More O2 can be carried
- Squeeze into narrow capillaries
- Allow O2 & CO2 Diffusion
NO mitochondria: ATP by anaerobic
means (advantage: do not use up O2
they carry)
RBCs carry blood group antigens
(A,B, O) on their cell membranes
Life span 120 days
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Destroyed in the body by RE cells: by
products are recycled (mostly at
Spleen)
It is Actions of the protein
coagulation factors to form fibrin
in response to injury to the blood
vessels
 Liquid Blood changes into a solid
◦ Primary Hemostasis
Process of blood clotting in response to injury
blood vessels (vasculature) and platelets play important role
Primary Hemostatic plug temporarily arrests bleeding.
Insoluble fibrin strands deposit on the initial plug to reinforce
and stabilize.
 The fibrin originates from soluble plasma proteins.
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◦ Secondary Hemostasis
 Actions of the protein coagulation factors form fibrin in response
to injury
 At this time, blood has changed into a solid state
◦ Fibrynolysis
 Clot is removed following healing of wound
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Primary
◦ Vascular System
 Endothelia
 Sub endothelia/collagen
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◦ Platelets
Secondary
◦ Coagulation System
 Plasma Proteins
 Cells: Platelets
◦ Fibrinolytic System
 Plasma proteins
 Cells: Platelets, Endothelia
Primary
Hemostasis
Secondary
Hemostasis
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Pathways to achieving a stable blood clot
◦ Extrinsic
◦ Intrinsic
◦ Common
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The ABO blood groups consists of:
◦ Two antigens (A and B) on the surface of the RBCs
◦ Two antibodies in the plasma (anti-A and anti-B)
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Agglutinogens and their corresponding
antibodies cannot be mixed without serious
hemolytic reactions
ABO
Group
Antigen
Present
Antigen
Missing
Antibody
Present
A
A
B
anti-B
B
B
A
anti-A
O
None
A and B
anti-A, anti-B,
anti-A,B
AB
A and B
None
None
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Presence of the Rh agglutinogens on RBCs is
indicated as Rh+ve 85% of population is +
Lack of antigen indicated as Rh –ve in 15% of
popn.
Anti-Rh antibodies are not spontaneously
formed only in Rh– individuals
However, if an Rh– individual receives Rh+
blood, anti-Rh antibodies form
A second exposure to Rh+ blood will result
in a typical transfusion reaction
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Blood typing involves determination of the antigens present
on an individual’s RBCs
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The two most common blood typing systems used are the
A-B-O method and the Rh method
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type A blood – contain “A” antigen on RBCs
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type B blood – contain “B” antigen on RBCs
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type AB blood – contains both A and B antigens
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type O blood – contain no A or B antigens
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Rh+ blood – contain Rh antigen
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Rh- blood – no Rh antigen
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When serum containing anti-A or anti-B
agglutinins is added to blood, agglutination
will occur between the agglutinin and the
corresponding Agglutinogens
Positive reactions indicate agglutination
NORMAL
100,000 - 400,000 CELLS/MM3
< 100,000
Thrombocytopenia
50,000 - 100,000
Mild Thrombocytopenia
< 50,000
Sever Thrombocytopenia
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Clotting time was used as a screening test to measure
all stages in the intrinsic coagulation system and to
monitor heparin therapy
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Severe hemophilia, a fibrinogenemia, and sever
fibrinolytic states cause a prolonged clotting time, as do
circulating anticoagulants ( inhibitors), and heparin
 The
surface of the glass tube
initiates the clotting process.
This test is sensitive to the
factors
involved
in
the
intrinsic pathway
 The
expected
range
for
clotting time is 4-10 min.
Normal HB level
Male: about
13-15 gm%
Female about
12-14 gm%
Clinical implications
Anemia means a deficiency of Hb which can
be caused by either too few RBCs or too
little Hb in the cells.
For diagnosis of anemia:
Hemoglobin
<13.0 g/dl
for males
< 12.0 g/dl. for females
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Another group of antigens found on the
RBC of the most of the people is the Rh
factor (named for the rhesus monkey )
 There are number of different antigens in
this group,
 This Rh antigen is termed as D and is often
indicated as RH D + or _ve
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