Blood

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PRESENTED BY: Nidhi Yadav

description

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.

Transcript of Blood

Page 1: Blood

PRESENTED BY: Nidhi Yadav

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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

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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.

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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

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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

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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.

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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.

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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

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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.

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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.

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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

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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.

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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.

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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.

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Hematopoiesis

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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-

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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.

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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

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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.

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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.

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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.

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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

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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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