Blood Blood What is it and why is it important?What is it and why is it important?

Dr. Ashish V. Jawarkar M.D.Dr. Ashish V. Jawarkar M.D.

Consultant PathologistConsultant Pathologist

Parul Sevashram HospitalParul Sevashram Hospital

BloodBlood

The average adult has about five The average adult has about five liters of blood living inside of their liters of blood living inside of their body, coursing through their vessels, body, coursing through their vessels, delivering essential elements, and delivering essential elements, and removing harmful wastes.removing harmful wastes.

Without blood, the human body Without blood, the human body would stop workingwould stop working

BloodBlood functions functions

Blood is the Blood is the fluid of growthfluid of growth, , transporting nourishment from transporting nourishment from digestion and hormones from glands digestion and hormones from glands throughout the body. throughout the body.

Blood is the Blood is the fluid of healthfluid of health, , transporting disease fighting transporting disease fighting substances to the tissue and waste substances to the tissue and waste to the kidneys.to the kidneys.

Bloods Major FunctionBloods Major Function

Blood is the Blood is the fluid of lifefluid of life, transporting , transporting oxygen from the lungs to body tissue oxygen from the lungs to body tissue and carbon dioxide from body tissue and carbon dioxide from body tissue to the lungs.to the lungs.

Blood PercentagesBlood Percentages

55 % plasma55 % plasma– PlasmaPlasma is the straw-colored liquid in is the straw-colored liquid in

which the blood cells are suspended. which the blood cells are suspended.

45 % cells45 % cells– Red blood cells (Erythrocytes)Red blood cells (Erythrocytes)– White blood cells (leukocytes)White blood cells (leukocytes)– Platelets (thrombocytes)Platelets (thrombocytes)

Blood Components Blood Components

PlasmaPlasmaPlasma is the relatively clear Plasma is the relatively clear liquid water , liquid water , sugar, fat, protein and salt solutionsugar, fat, protein and salt solution which which carries the red cells, white cells, platelets, and carries the red cells, white cells, platelets, and some other chemicals.  some other chemicals. 

Normally, 55% of our blood's volume is made Normally, 55% of our blood's volume is made up of plasma.  About 95% of it consists of up of plasma.  About 95% of it consists of water.  water. 

As the heart pumps blood to cells throughout As the heart pumps blood to cells throughout the body, plasma brings nourishment to them the body, plasma brings nourishment to them and removes the waste products of metabolismand removes the waste products of metabolism

Red blood cells (erythrocytes)Red blood cells (erythrocytes)

Red blood cells are biconcave discsRed blood cells are biconcave discs

erythrocytes erythrocytes

Red Blood CellsRed Blood CellsRed cells, or Red cells, or erythrocyteserythrocytes , cells without , cells without nuclei.  nuclei. 

Red cells normally make up 40-50% of the Red cells normally make up 40-50% of the total blood volume.  total blood volume. 

They transport oxygen from the lungs to all of They transport oxygen from the lungs to all of the living tissues of the body and carry away the living tissues of the body and carry away carbon dioxide.  carbon dioxide. 

The red cells are produced continuously in The red cells are produced continuously in our bone marrow from stem cells at a rate of our bone marrow from stem cells at a rate of about 2-3 million cells per second.   about 2-3 million cells per second.  

Cont.Cont.HemoglobinHemoglobin is the gas transporting is the gas transporting protein molecule that makes up 95% of a protein molecule that makes up 95% of a red cell. red cell. 

The red color of blood is primarily due to The red color of blood is primarily due to oxygenated red cells. oxygenated red cells. 

White Blood Cell (White Blood Cell (leukocytes)leukocytes)

White Blood CellsWhite Blood CellsWhite cells, or White cells, or leukocytesleukocytes , exist in variable , exist in variable numbers and types but make up a very small numbers and types but make up a very small part of blood's volume--normally only about 1% part of blood's volume--normally only about 1% in healthy people.  in healthy people. 

Most are produced in our bone marrow from Most are produced in our bone marrow from the same kind of stem cells that produce red the same kind of stem cells that produce red blood cells.blood cells.

Cont.Cont.Some white cells (called lymphocytes ) are Some white cells (called lymphocytes ) are the third line of defence, part of acquired the third line of defence, part of acquired immunity.  immunity.  – They seek out, identify, and bind to They seek out, identify, and bind to

alien protein on bacteria, viruses, and alien protein on bacteria, viruses, and fungi so that they can be removed. fungi so that they can be removed. 

– Other white cells (called neutrophils, Other white cells (called neutrophils, nk cells and macrophages ) form a nk cells and macrophages ) form a part of innate immunity and are the part of innate immunity and are the first line of defence.first line of defence.

Leukocytes(wbc’s) Total Leukocytes(wbc’s) Total

Neutrophils 60-70% Neutrophils 60-70% (N)EVER(N)EVER

Lymphocytes 20-25% Lymphocytes 20-25% (L)ET(L)ET

Monocytes 3-8%Monocytes 3-8% (M)ONKEYS(M)ONKEYS

Eosinophils 1-3%Eosinophils 1-3% (E)AT(E)AT

Basophils ½ to 1%Basophils ½ to 1%(B)ANANAS(B)ANANAS

Granulocytes Granulocytes

Granulocytes are white blood cells whose Granulocytes are white blood cells whose cytoplasm contains tiny granules. The cells are cytoplasm contains tiny granules. The cells are named according to the staining characteristics named according to the staining characteristics of the granules.of the granules.

NeutrophilsNeutrophilsNeutrophilsNeutrophils - the granules are purple - the granules are purple coloredcolored– Neutrophils are phagocytic cells; they Neutrophils are phagocytic cells; they

engulf foreign materialengulf foreign material– Part of second line of defencePart of second line of defence

EosinophilEosinophil

Have dense red granulesHave dense red granules

Play a part in allergic responsePlay a part in allergic response

Count is increased in allergiesCount is increased in allergies

BasophilsBasophilsBasophils have dark blue-staining Basophils have dark blue-staining granules. granules.

They are the least numerous blood cells.They are the least numerous blood cells.

Numbers are increased in leukemiasNumbers are increased in leukemias

Agranulocytes Agranulocytes

Agranulocytes are white blood cells Agranulocytes are white blood cells that have no distinct granules in their that have no distinct granules in their cytoplasm.cytoplasm.

LymphocytesLymphocytes have large single have large single nuclei that occupy most of the cells. nuclei that occupy most of the cells.

They are an important part of the body's They are an important part of the body's immune system.immune system.

LymphocyteLymphocyte

Types of lymphocytesTypes of lymphocytes

T-cellsT-cells

B- cellsB- cells

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Third line of defence - Lymphocytes

Lymphocytes are a type of white blood cell found in the blood or lymph nodes and made by bone marrow. There are several types of lymphocyte, including:

T-lymphocytes – recognise antigens on pathogens and either attack them directly or co-ordinate the activity of other cells of the immune system.

B-lymphocytes – recognise antigens and produce special chemicals called antibodies.

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B lymphocytes

Antibodies are specialY-shaped proteins produced byB-lymphocytes in response to antigens.

Antibodies work by binding to antigens on pathogens, ‘labelling’ them and causing them to clump together. The pathogen can then be destroyed by:

the antibodies themselves.

phagocytosis by macrophages

T-lymphocytes

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Antibodies

Each different type of antigen causes a different type of antibody to be produced.

An antibody can only bind to the antigen that caused it to be produced.

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Delayed response

The B-lymphocyte that produces the correct antibody for the antigen begins dividing to produce many more antibody-producing cells.

It takes a few days to produce enough antibodies to destroy the pathogen. This means there is delay between infection and the person beginning to feel better.

Once a pathogen has been destroyed, a few memory cells remain. These recognize the pathogen if it re-infects, and make the immune response much quicker and more effective. This is called active immunity.

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ContCont

Monocytes Monocytes are the largest of the are the largest of the white blood cells. In tissues k/a white blood cells. In tissues k/a macrophagesmacrophages

They have large pleomorphic They have large pleomorphic (variously shaped) single nuclei and (variously shaped) single nuclei and function mainly as phagocytic function mainly as phagocytic (engulfing) cells . (engulfing) cells .

They are important in the long-term They are important in the long-term cleanup of debris in an area of injury.cleanup of debris in an area of injury.

Cont.Cont.

Monocyte (left)

Watch this and many more Watch this and many more animations @ animations @ http://highered.mcgraw-hill.com/siteshttp://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter/0072495855/student_view0/chapter2/animation__phagocytosis.html2/animation__phagocytosis.html

Platelets (Platelets (thrombocytes)thrombocytes)

Platelets

PlateletsPlateletsPlatelets , or Platelets , or thrombocytesthrombocytes , are cell , are cell fragments without nuclei that work with fragments without nuclei that work with blood clotting chemicals at the site of blood clotting chemicals at the site of wounds. wounds. – They do this by adhering to the walls of blood They do this by adhering to the walls of blood

vessels, thereby plugging the rupture in the vessels, thereby plugging the rupture in the vascular wall.  They also can release coagulating vascular wall.  They also can release coagulating chemicals which cause clots to form in the blood chemicals which cause clots to form in the blood that can plug up narrowed blood vessels.  that can plug up narrowed blood vessels. 

  

Blood loss Blood loss When the human body loses a little When the human body loses a little bit of blood through a minor wound, bit of blood through a minor wound, the platelets cause the blood to clot the platelets cause the blood to clot so that the bleeding stops. so that the bleeding stops.

Because new blood is always being Because new blood is always being made inside of your bones, the body made inside of your bones, the body can replace the lost blood.can replace the lost blood.

Blood replacement Blood replacement

When the human body loses a lot of When the human body loses a lot of blood through a major wound, that blood through a major wound, that blood has to be replaced through a blood has to be replaced through a blood transfusion from other people.blood transfusion from other people.