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It is a brief review on blood and its cellular components. The ppt contains knowledge about types of blood, blood coagulation pathway and disorders of blood.
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PRESENTED BY: Nidhi Yadav
Blood is a connective tissue. It provides one of the means of
communication between the cells of different parts of the
body and the external environment.
Blood is living tissue that carries oxygen and nutrients to all
parts of the body, and carries carbon dioxide and other waste
products back to the lungs, kidneys and liver for disposal. It
also fights against infection and helps heal wounds, so we
can stay healthy.
The average adult has about 6 liters of blood. Blood is
slightly alkaline with a pH of about 7.4
It carries oxygen from lungs to the tissues and carbon dioxide from the tissues to
the lungs for excretion.
It carries nutrients from the alimentary tract to the tissues and cell wastes to
excretory organs.
Transports hormones secreted by endocrine gland to their target glands and
tissues.
Deliver O2.
Maintain temperature, pH, and fluid volume.
Protection from blood loss- platelets.
Prevents from infection- antibodies and WBC.
Transport hormones.
Contains clotting factors that coagulate blood, minimizing its loss from ruptured
blood vessels.
Composition of Blood
COMPOSITION OF BLOOD
PLASMA (55%) CELLS (45%)
RBC erythrocytes
WBC leucocytes
Plateletes thrombocytes
Granulocytes Agranulocytes
Neutrophills Basophills Eosinophills Monocytes Lymphocytes
Small lymphycytes
Large lymphocytes
Plasma
•Water (90%) •Plasma proteins (Albumins, Globulins,
Fibrinogen) •Inorganic salts (Sodium Chloride, sodium
bicarbonate, potassium, magnesium phosphate,
iron, calcium, copper, iodine, cobalt) •Nutrients (monosacharides, amino acids, fatty
acids, glycerol, vitamins) •Organic waste products (urea, uric acid,
creatinin) •Hormones.
Gases (Oxygen, Carbon dioxide, Nitrogen
Plasma Blood is composed of a straw colored transparent fluid, plasma, in which different
types of cells are suspended.
The constituents of plasma are:
1. Water (90%)
2. Plasma Proteins (7%):
Responsible for creating the osmotic pressure of blood. (25 mmHg or 3.3 KPa). If plasma protein level falls, osmotic pressure is also reduced, and fluid moves into the tissue (edema) and cavities.
a. Albumin
These are formed in the liver. They are the most abundant plasma proteins and their main function is to maintain a normal plasma osmotic pressure.
b. Globulins
Formed in liver and lymphoid tissue. Act as antibodies (immunoglobulins). They bind to and neutralize, foreign materials. (antigens)
c. Fibrinogen:
Play important role in blood coagulation.
3. Inorganic Nutrient Salts
Required to maintain the pH of blood (7.3-7.4)
4. Nutrients
Monosaccharide, amino acids, fatty acids, glycerol and vitamins together with mineral
salts required by the body cells to provide energy, heat, and for the synthesis of other
blood components.
5. Organic Waste Products
Urea, uric acid, and creatinine are the waste products. They are formed in the liver and
conveyed in blood to the kidneys for excretion.
6. Hormones
Hormones pass directly from the cells of the glands into the blood which transports them to
their target tissues and organs.
7. Gases
Oxygen, carbon dioxide, nitrogen are transported around the body in solution in plasma.
Cellular Content Of Blood
1. Erythrocytes (Red Blood Cells)
These are circular, biconcave, non nucleated discs with a diameter
of 7 microns.
Life span= 120 days
production time= 7 days
Erythropoisis/ RBC Production
Erythrocytes are formed in red bone marrow, which is present in
the end of long bones and in flat and irregular bones.
The process of development of red blood cells from pluripotent
stem cells is called erythropoiesis.
It is characterized by 2 features
Maturation of the cell.
Formation of haemoglobin inside the cell.
Maturation of cell
During this process the cell decreases in size and loses its nucleus. These changes depend on presence of
vitamin B12 and folic acid. These are present in sufficient quantity in a normal diet containing dairy products,
meat and green vegetables. Deficiency of vitamin B12 and folic acid leads to impaired red cell production.
Stem cells (heamocytoblast) are able to generate all types of blood cells. Conversion of haemocytoblast to
proerythroblast is process lead to formation of erythrocytes under the influence of erythropoietin and
presence of nutrient factors vitamin B12 and folic acid. This process lead to increased formation of ribosome
leading to large number of smaller sized erythroblasts. Haemoglobin synthesis starts on these ribosomes. The
synthesized haemoglobin then starts occupying thespace of the other organelles. Slow degeneration and
ejection of these organelles further reduces the size of the cell and forms normoblasts. Later haemoglobin
almost completely occupies the cytoplasmic space and ejects out the nucleus and remaining organelles finally
forming a reticulocytes. They mature to form erythrocytes.
Haemoglobin
Haemoglobin is a complex protein, consisting of globin and an iron-containing substance called haem, and is
synthesized inside developing erythrocytes in red bone marrow. Haemoglobin in mature erythrocytes
combines with O2 to form oxyhaemoglobin, giving arterial blood its characteristic red color.
Stem cell
Hemocytoblast
Proerythro- blast
Early erythroblast
Late erythroblast
Normoblast
Phase 1 Ribosome synthesis
Phase 2 Hemoglobin accumulation
Phase 3 Ejection of nucleus
Reticulo- cyte
Erythro- cyte
Committed
cell
Developmental pathway
2. W.B.C (Leukocytes)
Granulocytes
Granules are present in the cytoplasm.
Neutrophills
They are stained with neutral dyes and takes up violet color. Therefore they are named as neutrophills. Neucleus has 4 lobes and they contain fine granules in the cytoplasm. The diameter of the neutrophills is 10-12 µ.
Eosinophills
They are stained with acidic dye and take up red color. Nucleus has 2 lobes. Cytoplasm contains coarse granules. Their size is 10-12 µ.
Basophills
They are stained with basic dyes and take up blue color. Granules are coarse. Their size is 8-10 µ.
Agranulocytes Granules are not present in the cytoplasm. a. Monocytes 18 µ in diameter. Amongst the W.B.C they are the largest in size.
They contain an asentric nucleus which are notched from inner side.
b. Lymphocytes In lymphocytes nucleus covers almost the cell hence there is less
cytoplasm in the cell. Large lymphocytes: 10-15 µ. Small lymphocytes: 8-10 µ in size.
3. Platelets/ Thrombocytes
Platelets are round, oval plates with biconvex surfaces. They
are called thrombocytes because they involve in the process of
thrombus formation. (clotting). The main function of platelets
is to initiate clotting by converting prothrombin into thrombin.
Hematopoiesis
Type of Blood/ABO Classification of Blood
Antigens present on RBC surface specify blood type. Major antigen group is
Type A blood has only A antigens
Type B has only B antigens
Type AB has both A & B antigens
Type O has neither A or B antigens
Rh Factors/Rh antigen
Scientists sometimes study Rhesus monkeys to learn more about the human anatomy because there are
certain similarities between the two species. While studying Rhesus monkeys, a certain blood protein was
discovered. This protein is also present in the blood of some people. Other people, however, do not have the
protein. The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus) factor.
If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If your blood does not
contain the protein, your blood is said to be Rh negative (Rh-).
A+ A-
B+ B-
AB+ AB-
O+ O-
Blood Coagulation or Blood Cloting/ Haemostasis
When a blood vessel is damaged, loss of blood is stopped and healing occurs in a series of process
called haemostasis.
Time required to clot blood is 3-8 minutes.
1. Vasoconstriction
when platelets come in contact with a damaged blood vessel, their surface becomes sticky and they
adhere to the damaged wall. they then release serotonin (5-HT), which constricts the vessel, reducing
blood flow through it.
2. Platelet Plug Formation
The adherent platelets clump to each other and release other substances, including ADP, which attract
more platelets to the site and form a platelet plug.
3. Coagulation/ Blood Clotting
Blood clotting results in formation of an insoluble thread-like mesh of fibrin which traps blood cells
and is much stronger than the rapidly formed platelet plug. in the final stage of this process
prothrombin activator acts on the plasma protein prothrombin converting it to thrombine. Thrombin
then acts on another plasma protein fibrinogen and converts it to fibrin. Coagulation process follows
by 2 pathways :extrinsic pathway and intrinsic pathway.
Factors
XII- Hageman Factor (Surface Factor)
XI- Plasma thromboplastin
IX- Serine Protease
VII- stable factor
XIII-fibrin stabilizing factor
X- stuart factor
V- accelerated globulin
VIII- activated globulin
PL- platelet membrane phospholipid
Ca++ - calcium ions
TF- tissue factor a: active form A
4. Fibrinolysis
After a clot has formed the process of removing it and healing the
damaged blood vessel begins, called as fibrinolysis. An active substance
called plasminogen is present in the clot and is converted to the enzyme
plasmin by activators release from damaged endothelial cells. Plasmin
initiates the breakdown of fibrin to soluble products that are treated as
waste material and removed by phagocytosis.
Disorders
1. Disorders of erythrocytes
Anaemias
It is the disease involving deficiency in the number of red blood cells or deficiency of
haemoglobin. there is a decrease in oxygen carrying capacity of blood. symptoms are:
breathlessness, tiredness, loss of appetite and pallor of skin. types of anemia are:
I. Iron Deficiency Anemia
Deficiency of iron due to low dietery intake or decreased absorption.
II. Megaloblastic Anemia
Deficiency of either vitamin B12 or folic acid. both are necessary for the maturation of red
blood cells.
III. Hemolytic Anemia
Increased destruction of red blood cells. It occurs due to i. hereditary disorders.ii.
mechanical injury to red blood cells. Iii. Infections likemalaria.
IV. Sickle cell anemia: It is a haemolytic condition. when oxygen level is low the
haemoglobin molecules may aggregate and cause RBC to change from biconcave discs to
sickle shaped.
V. Aplastic Anemia
Occurs due to suppression of bone marrow function. It can be
caused by drugs, chemicals,irradiation or malignant diseases.
Polycythemia
In this condition there is an abnormal increase in the number of
red blood cells. This increases the viscosity of blood. This
decreases the rate of flow and increases risk of intravascular
clotting.
2. Disorders of leucocytes
Leucocytosis:
It is an increase in the total number of white blood cellsbeyond 10,000 per cubic
millimeter. It is of following types.
I. Neitrophilia: An increase in the number ofneutrophils. It occurs in many
inflammatory conditions.
II. Eosinophilia: An increase in the number of eosinophils. It is anindication for
allergic manifestations.
III. Leukemia: It is cancerous condition characterized by an overproduction of white
blood cells.
Leucopenia
Low WBC count.
Leukemias
Cancerous condition involving WBC. It characterized by overproduction of
W.B.C
3. Disorders of platelets
They occur in the form of thrombocytopenia.itis a condition
where there is a decrease in platelet count.
4. Disorders of Haemostasis
Thromboembolytic disorder
Undesirable clot formation.
Bleeding Disorder
I. Thrombocytopenia
Too few platelets causes spontaneous bleeding due to
suppression or destruction of bone marrow.
II. Haemophillia
Hereditary bleeding disorder. Symptoms include prolonged
bleeding.
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