THE BLOOD Presented By : Dr. Ullas Saxena, JR - 1Oral Medicine & Radiology

Blood is a specialized connective tissue containing intracellular fluid plasma and blood components – RBCs , WBCs and blood platelets.

An average 70 kg man has almost 5L blood (5.5 kg).

Blood circulates throughout the body and supports the functions of all other body tissues.

Blood integrates tissues and organs and provide a special means of communications .

Blood is called – The river of life

BLOOD

Antoni van leeuwenhock- pioneer microscopy-blood

William Hewson – father of haematology Paul Ehrlich- poineer in use of dyes William Castle- extrinsic and intrinsic factors

Through the eyes of the past :

William Harvey 1628 background for blood transfusion

Richard Lower 1665 -1st blood transfusion - dog

1st human transfusion- 1667-sheep Jean Baptiste Denis - sheep to man

Lavoisier discovered- 18th century role of blood in transporting O2 from lungs to the tissues.

Karl landsteiner 1901 ->O-A-B blood groups 1940 -> Rh blood group (WIENER)

Respiration: transport of O2 and CO2. Transport: hormone, nutrients, metabolic

waste. Excretion of metabolic wastes to the kidney,

lungs and skin. Regulation of body temperature by

distribution of body heat. Defense against infections (WBCs,

antibodies). Maintenance of acid-base balance. Nutrition: transport of absorbed food

material.

FUNCTIONS OF BLOOD:

Specific gravity:-Whole blood:1.055 -1.065 kg/m³

Plasma: 1.024 -1.028 kg/m³ • Viscosity: 5-6 times that of water. Mass:6-8% of the body weight. Blood volume:~ 8% of body weight.~ 86%

(ml/kg body weight). 5-6 Liters in adults, [Infants have a larger blood volume in proportion to body weight than adults]. Osmotic pressure: 7-8 atmosphere at body

temperature

Physical properties of blood:

Generally , blood is red in color due to a pigment present in blood called haemoglobin.

Arterial blood is scarlet red while venous blood is purple red.

Ph of blood is 7.4.

Color of blood :

Composition of Blood:An adult human has about 4–6 liters of blood .Blood consists of several types of cells floating around in a fluid called plasma.

1. The red blood cells (RBCs) contain haemoglobin, a protein that binds oxygen. RBCs transport oxygen and remove carbon dioxide from the tissues.

2. The white blood cells fight infection.3. The platelets help the blood to clot.4. The plasma contains salts and various

kinds of proteins .

Plasma proteins – albumin , globulin and fibrinogen.

Carbohydrates – glucose Non protein substances – creatin ,

creatinine, xanthine , hypoxanthine , urea and uric acid.

Enzymes and antibodies . Inorganic substances - k , mg,cl, iodide ,

iron and phosphate. Gases – oxygen , carbondioxide.

Other constituents of blood :

CONSTITUENTS PLASMA RBC WATER 91-95% 65% SOLIDS 8-9 % 35% PROTEIN 6-8 gm % 31-

33% SPECIFIC GRAVITY 1.026

Gross composition of Plasma and Blood Cells

The hematocrit (haematocrit), also known as packed cell volume (PCV) or erythrocyte volume fraction (EVF)- volume percentage (%) of red blood cells in blood.

Anticoagulant added to whole blood in presence of EDTA , Oxalate, Citrate and Heparin – no clotting of blood

blood centrifuged in a hematocrit tube for 30 minutes at speed of 300 rpm.

tube is taken out and reading is taken.

PCV decreases in Anemia and is increased in Polycythemia.NORMAL PCV :In males – 40 to 45 %In females – 38 to 42 %

The sequence of settlement of blood components: i. At bottom – Red blood cells (Erythocytes)- 45% of whole blood

ii. In the middle - White Buffy coat (Leucocytes Thrombocytes and platelets- >1% of the whole blood)

iii. On the Top – Plasma (55% of whole blood)

Rate of Sedimentation of Erythrocytes. ESR –Non specific indicator of infection. ESR - For monitoring status of chronic

inflammatory diseases . Normal Values: i. For males: 3 to 10 mm/hr ii. For females: 5 to 15 mm/hr.

ERYTHROCYTE SEDIMENTATION RATE (ESR)

Red blood cells settle upon one another at the Bottom of the Test tube.

This pattern of settlement of red blood cells upon one another is known as “ Rouleaux formation”.

The rate of settlement of red blood cells - erythrocyte sedimentation rate or ESR.

ESR is measured by :i. Wintrobe ‘s methodii. Westergren ‘s method

Normal Values:i. For males: 3 to 10 mm/hrii. For females: 5 to 15 mm/hr.

Chronic inflammatory disease (collagen and vascular diseases) increases ESR.Polycythemia decreases ESR.

Some interferences which increase ESR: increased level of fibrinogen, gamma

globulins. technical factors: tilted ESR tube, high room

temperature. Some interferences which decrease ESR: abnormally shaped RBC (sickle cells,

spherocytosis). technical factors: short ESR tubes, low room

temperature, delay in test performance (>2 hours), clotted blood sample, excess anticoagulant, bubbles in tube.

WHOLE BLOOD

NO ANTICOAGULANT

CLOT FORMATION

CENTIFRUDGE CLOT +CLEAR YELLOWISH FLUID (SERUM)

SERUM ( PLASMA – FIBRINOGEN ) C

ENTIFRUDGE

Blood Plasma - Composed of approximately 90% water Includes many dissolved substances Nutrients, Salts (electrolytes), Respiratory gases,

Hormones, Plasma proteins, Waste products.

PLASMA

Plasma proteins - Most abundant solutes in plasma

Most plasma proteins are made by liver

Various plasma proteins include Albumin—regulates osmotic

pressure Globulin – transports harmones Clotting proteins—help to stem

blood loss when a blood vessel is injured

Antibodies—help protect the body from pathogens .

Acidosis - Blood becomes too acidic Alkalosis - Blood becomes too basic

NORMAL VALUESTotal proteins - 7.3 gm% (6.4 to 8.3gm%)

Serum albumin - 4.7 gm %

Serum globulin - 2.3 gm%

Fibrinogen - 0.3 gm%

A-G Ratio: 1.7

1. Proteins 2. Carbohydrates 3. Fats 4. Amino acids 5. Non protein nitrogenous substances: 6. Internal secretions like hormones. 7. Enzymes -- amylase, carbonic anhydrase,

alkaline phosphatase, acid phosphatase, lipase, esterase, protease and transaminase.

8. Antibodies -- immunoglobulins.

Organic Substances of Plasma

Sodium Calcium Potassium Magnesium Chloride Iodide Iron Phosphates Copper

GASES PRESENT IN PLASMA: O2 & CO2

Inorganic Substances of Plasma

Help in coagulation of blood- fibrinogen Defense mechanism - gamma globulin Transport of harmones - albumin and

globulin Maintain acid base balance in blood Provide viscosity to blood Help in ESR regulation Help in maintaining suspension stability of

RBCS Produce trephone bodies in blood culture

along with WBCS

FUNCTIONS OF PLASMA PROTEINS

Blood levels of some important substances

Erythrocytes - Red blood cells (RBCs) Leukocytes - White blood cells (WBCs) blood Platelets

Formed Elements of blood

RED BLOOD CELLS Erythrocytes (red blood

cells or RBCs) - Main function is to carry oxygen .

Anatomy of circulating erythrocytes

Biconcave disks, essentially bags of hemoglobin, anucleate (no nucleus).

RBCS :Normal size : 7.5 microns in diameter and thickness 2.5 microns at periphery and 1 micron at the center.

Total Number Of RBCs:Average :

4-5 millions per mm³In males : 5 million per mm ³In females : 4.5 per mm ³

Homeostatic imbalance of RBCs : Anemia is a decrease in the oxygen-

carrying ability of the blood . Sickle cell anemia (SCA) results from

abnormally shaped hemoglobin . The red blood cells become sickle shaped. Polycythemia is an excessive or abnormal

increase in the number of erythrocytes .

RBCs are destroyed in spleen. Spleen is called - graveyard of RBCs.

Crucial in the body’s defense against diseases Originates from the same hemocytoblast stem cell as the red cells and platelets.

Produced normally in a proportion of about1/700 the number of red cells.

Colorless, have nuclei and granules which can be made visible by staining.

These are complete cells, with a nucleus and organelles.

Able to move into and out of blood vessels (diapedesis) .

4,000 to 11,000 WBC per cubic millimeter of blood .

Leukocytes (White Blood Cells)

: Leukocytosis / WBC count above 11,000

leukocytes/mm³ Generally indicates an infection

Leukopenia - Abnormally low leukocyte level Commonly caused by certain drugs such as

corticosteroids and anticancer agents Leukemia - Bone marrow becomes

cancerous, turns out excess WBCs.

Disorders of WBCs

Neutrophils Lymphocytes Monocytes Eosinophils Basophils

List of the WBCs from most to least abundant :

Granulocytes - Granules in their cytoplasm can be stained, include basophils, eosinophils & neutrophils (BEN).

Have observable granules when stained. Neutrophils are 60-65% of leukocytes, the most common

wbc, they perform active and passive phagocytes. PMN leucocytes (Polymorphonuclear = many shaped

nucleus) Agranulocytes - Lack visible cytoplasmic granules, Include

lymphocytes and monocytes.

Types of leukocytes :

Lymphocytes - Play an important role in the immune response

Monocytes - Function as macrophages . Important in fighting chronic infection .

Types of Agranulocytes

Platelets - Needed for the clotting process

Normal platelet count = 250,000- 300,000/mm³.

platelet life: new platelets released from megakaryocytes remain functional till 7-11 days. old platelets are

decomposed in the liver and spleen.

BLOOD PLATELETS - THROMBOCYTESFunction of blood platelets:

1. platelets are responsible for wound healing .

2. platelets attach to the exposed vessel3. platelets change fibrinogen into fibrin this fibrin creates a mesh onto which red blood cellscollect and clot the clot stops more blood from leaving the body 4.prevents bacteria from entering the body.

RBC COUNT- Men : 4- 5 millions / mm³ Women : 4.5million / mm³ Total number of red cells = 4 – 5 millions / mm³ WBC COUNT - Men and women : 4000 – 11000/ mm³ PLATELETS : Men and women - 25 , 000/ mm³ Hb - Men14 –16 g/l Women - 12 –16 g / l PCV (Haematocrit): Men :0.42 –0.52 l/l Women :0.37 –0.47 l/l

Normal Values --

HAEMOGLOBINIron-containing protein that binds strongly, but reversibly to oxygen. Each hemoglobin molecule has four oxygen binding sites .Each erythrocyte has 250 million hemoglobin molecules .Normal blood contains 12–18 g of hemoglobin per 100 mL blood.

Structure : Globular and Conjugated protein, (Haem+

Globin). Made of 4 subunits (Quarternary structure) 4 globins + 4 haems → Haemoglobin. Binds O2 to Haemgroup to form

Oxyhaemoglobin. Hb+ 4O2→Hb(O2)4

General Description of Hb :Hemoglobin, a protein (a major solute) found in the red blood cells, contains Fe (iron) and serves as the principal transporter of molecular oxygen in the blood of humans as well as in many other animals. The hemoglobin picks up oxygen in the lungs and transfers it to the tissues where it is used by cells.

There are two major parts of hemoglobin: 1. Heme: A porphyrin with an Fe in the center. Porphyrin rings are found throughout biological

systems and serve many different roles including photosynthesis in green plants, delivering O2 in muscles (myoglobin) and transporting O2 in blood (hemoglobin).

2. Globin: Globin is the protein (polypeptide) surrounding the heme. Nomenclature:globin + heme (Fe2+) = hemoglobinglobin + heme (Fe3+) = methemoglobinThe overall structure of haemoglobin consists of four chains – two alfa and two beta chains

When hemoglobin is carrying O2 it is called oxyhemoglobin and when it is not carrying O2 it is known as deoxyhemoglobin.

Deoxy and oxyhemoglobin have different colors, thus explaining why blood in our arteries (oxyhemoglobin) is brighter red than the blood in our veins.

Oxygen binds to the Fe of the heme group because it has lone pairs which can coordinate to the Fe.

Features Of Haemoglobin

In Adults:Hb : ~ 97% α2β2HbF: <1% α2γ2HbA2: 2.5 – 3.5% α2 δ2 At Birth:HbF: β2 γ2HbA :α2 β2During Embryonic life:Hb Gower 1Hb Gower 2Hb Portland

Types Of Haemoglobins at various life stages

Hb + 0 2 - oxyhemoglobin Hb + C02 – carbhemoglobin Hb + CO – carboxyhemoglobin Hb + S - Sulfhemglobin Hb + potassium ferricyanide -

Methemoglobin

Derivatives of haemoglobin

In Lungs: High PO2, ↓H+,

↓CO2→high affinity of Hb for O2 (O2dissociation curve shifts to left).

In Tissues Low P O2, ↑H+,

↑CO2, ↑2,3 DPG →Low affinity of Hb for O2 (O2dissociation curve shifts to right )

THE BOHR EFFECT

Increase in the concentration of carbon dioxide will displace oxygen from hemoglobin and binding of Oxygen with Hemoglobin in turn will displace Carbon dioxide from blood. This phenomenon is referred to as the Haldane Effect.

HALDANE EFFECT

Coagulation is clotting of blood. Injured tissues release tissue factor (TF) . Prothrombin activator converts prothrombin

to thrombin (an enzyme) . Thrombin joins fibrinogen proteins into hair-

like molecules of insoluble fibrin Fibrin forms a meshwork (the basis for a

clot). Blood usually clots within 3 to 6 minutes .

Blood Coagulation and its Pathways:

BLOOD CLOTTING FACTORS

EXTRINSIC PATHWAYThe extrinsic pathway is activated by external trauma that causes blood to escape from the vascular system. This pathway is quicker than the intrinsic pathway. ( Factors involved – III-VII-X-V .)

INTRINSIC PATHWAY :Begins to trauma to blood itself.( Factors involved -III, XII-XI-IX-VIII-X-V)

Interactions between the pathways:

Factor XIIa enhances Factor VII activity.

The VII-TF complexes that form during the extrinsic pathway can activate Factor IX of the intrinsic pathway, and this ability is augmented by the presence of Factor Xa.

Interaction between two pathways:

CLOT RETRACTION Serum = plasma - fibrinogen Role of calcium - in clot retraction Role of vitamin K- prothrombin and VII,IX and X Diff b/w extrinsic and intrinsic pathways extrinsic pathway- 15 sec – explosive intrinsic pathway – 1 to 6 min - slower

Endothelial surface factors - smoothness prevent contact activaton

glycocalyx repels clotting factors and platelets

protein Thrombomodulin + thrombin complex activates – protein C (inactivate V and VIII)

Antithrombin action of Fibrin and Antithrombin III prevents blood clotting inside the body.

HEPARIN inactivates – IX,X,XI,XII

Prevention of blood clotting in normal vascular system- intravascular anticoagulants

Lysis of blood clot inside the blood vessel – Fibrinolysis Plasma protein – euglobulin called plasminogen

(profibrinolysin) when activated become plasmin (fibrinolysin)

Plasmin digests fibrin fibres as well as coagulant factors I,II, V, VIII and XII

LYSIS OF BLOOD CLOT

HEPARIN- IV inj 0.5to 1 mg/kg body wt postpone clotting by 3 to 4 hr

Coumarin derivatives- Dicoumoral and Warfarin inhibit action of vit k

EDTA – removes calcium from blood . Oxalate compounds- calcium oxalate Citrates – Na, NH3,K citrate Citrate used in blood bank as acid citrate

dextrose (ACD) or citrate phosphate dextrose (CPD) to store blood.

Other- genetically engineered steptokinase for treating intravascular clots

Chemical agents to prevent clotting-ANTICOAGULANTS

Bleeding time is the interval between the moment when bleeding starts and the moment when bleeding stops. Normal bleeding time (Duke’s method) is to 4 minutes. Bleeding time is prolonged in purpuras, but normal in coagulation disorders like haemophilia.

Bleeding time is noted as in Duke’s method. Normal value is 2 to 7 minutes

Bleeding time :

Physical method to prevent blood clotting

Substance which accelerate the process of coagulation of blood are called hemostatic agent or procoagulants

THROMBIN SNAKE VENOM proteolytic enzymes enhance clotting by activating

clotting factors EXTRACTS OF LUNGS AND THYMUS thromboplastin -- rapid blood coagulation SODIUM OR CALCIUM ALGINATE activate Hageman factor OXIDIZED CELLULOSE activate Hageman factor

PROCOAGULANTS

BLEEDING TIME 2 Methods – DUKES method –> 2 – 6 min IVY’S method -> 3 – 6 min

Prolonged in purpura

CLOTTING TIME Capillary glass tube method -> 3 – 8 min at 370c LEE and WHITE method – glass tube 6-12 min - silicon tube 20-60 min Prolonged in hemophilia.

TESTS FOR CLOTTING

PROTHROMBIN TIME (PT) Time taken by blood to clot after adding

tissue thromboplastin is called prothrombin time.

PT indicates total quantity of prothrombin present in blood.

Normal PT –> 10 - 12 seconds. Prolonged in defeciency of prothrombin &

factors I, V, VII and X. Normal in hemophilia.

Clotting time is the interval between the moment when bleeding starts and the moment when the fibrin thread is first seen.

Normal value is 3 to 10 minutes. Vitamin K dependent factors are 2 , 7, 9 and

10, which help in coagulation of blood .

Clotting time :

Undesirable Clotting - : Thrombus - A clot in an unbroken blood

vessel Can be deadly in areas like the heart . Embolus - A thrombus that breaks away and

floats freely in the bloodstream Can later clog vessels in critical areas such

as the brain .

Coagulation of blood inside the blood vessel -thrombosis

Normally, blood does not clot in blood vessel because --

All clotting factors are in inactive form.

Smooth endothelial lining of blood vessels

Continuous movement of blood Natural anticoagulants like heparin

THROMBOSIS

Thrombocytopenia - Platelet deficiency Even normal movements can cause bleeding

from small vessels requiring platelets for clotting

Hemophilia - Hereditary bleeding disorder where normal clotting factors are missing.

Bleeding Disorders

HEMOPHILIA A – deficiency of factor VIII

HEMOPHILIA B ( CHRISTMAS DISEASE) – Deficiency of factor IX

HEMOPHILIA C- deficiency of factor XII WON WILIBRAND DISEASE – Bleeding

time is increased.

Types of Heamophilia :

Haemopoisis :The process of formation of blood. Erythropoisis : Formation of Erythrocytes. Leucopoisis : Formation of Leucocytes Thrombopoisis : Formation of Thrombocytes.

Haemopoisis

PROCESS PRODUCT Erythropoesis RBCS

Leucopoiesis WBCS

Granulopoiesis GRANULOCYTES

Lymphopoiesis LYMPHOCYTES

Megakaryocytes PLATELETS

Fetal Life 1-2 months - Yolk Sac 2-6 months - Spleen 1-9 months – Liver From 4 months –bone marrow At birth - bone marrow Adult life – bone marrow Red blood cells are destroyed in spleen. Spleen is called graveyard of RBCS.

Site of Haemopoisis

1. vitamin K 2. vitamin B 12 3. viamin C 4. iron 5. erythopoietin harmone – secreted by kidney 6. BPA – bursa promoting activity

FACTORS NECESSARY FOR FORMATION OF BLOOD:

Human Blood Groups: Blood contains genetically determined

proteins . Antigens (a substance the body recognizes as

foreign) may be attacked by the immune system .

Antibodies are the ―recognizers , are proteins produced in response to antigen

Blood is typed by using antibodies that will cause blood with certain proteins to clump (agglutination) .

The presence of both antigens A and B is called type AB .

The presence of antigen A is called type A . The presence of antigen B is called type B . The lack of both antigens A and B is called type

O . Blood type AB can receive A, B, AB, and O

blood (Universal recipient) . Blood type B can receive B and O blood Blood type A can receive A and O blood Blood type O can receive O blood (Universal

donor) .

Universal Acceptor and Universal Donor:

The AB0 and Rhesus (Rh) systems - used for blood transfusion.Not all blood groups are compatible with each other. Mixing incompatible blood groups leads to blood clumping or agglutination, which is dangerous for individuals.

Blood Transfusion People with blood group O are called "universal donors" and people with blood group AB are called "universal receivers."

              

Blood group A blood group A, has A antigens on the surface of RBCs and B antibodies in blood plasma.

                Blood group Bblood group B, has B antigens on the surface of RBCs and A antibodies in blood plasma.

AB0 blood grouping system

                

              

              Blood group AB blood group AB, has both A and B antigens on the surface of RBCs and no A or B antibodies at all in blood plasma.

                

Blood group Oblood group O (null), has neither A or B antigens on the surface RBCs but both A and B antibodies are present in blood plasma.

SEROLOGYSerology: This is a direct detection of the ABO antigens.

This form of testing involves two components:

a) Antibodies that are specific at detecting a particular ABO antigen on RBCs.          b) Cells that are of a known ABO group

Blood Group

Antigens Antibodies Can give blood to

Can receive blood from

AB A and B None AB AB, A, B, O

A A B A and AB A and O

B B A B and AB B and O

O None A and B AB, A, B, O O

Rh Blood Groups : Named a/ c presence or

absence of one of eight Rh antigens (agglutinogen D).

Most Americans and Asians are Rh+ (Rh positive) .

Problems can occur in mixing Rh+ blood into a body with Rh– (Rh negative) blood .

First discovered in Rhesus monkeys in 1939, by Philip Levine and Rufus Stetson .

Hemolytic Disease of new born : Danger occurs only when the

mom is Rh– and the dad is Rh+, and the child inherits the Rh+ factor.

Rho GAM shot can prevent buildup of anti-Rh+ antibodies in mother.

The mismatch of an Rh– mother carrying an Rh+ baby can cause problems for the unborn child .

The first pregnancy usually proceeds without problems .

The immune system is sensitized after the first pregnancy .

In a second pregnancy, the mother’s immune system produces antibodies to attack the Rh+ blood (hemolytic disease of the newborn) .

HARRISON – TEXTBOOK OF GENERAL MEDICINE 21TH EDITION

GYTON – TEXTBOOK OF PHYSIOLOGY 12 TH EDITION

DAVIDSON TEXTBOOK OF MEDICINE – 20 TH EDITION

www.redcross.org/blood www.americasblood.org/ www.bloodjournal.org/

BIBILOGRAPHY

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