BLOOD

      BLOOD

Definition:-

          It is a specialized connective tissue, which is in fluid form having intercellular substance known as Plasma. In which RBC, WBC, Platelet are suspended.

RBC:-          Red blood cell (Erythrocytes)

WBC:-         White blood cell (leucocytes)

Platelets (thrombocytes)

Properties of blood:-

1. Colour :-

          Blood is red in colour.

2. Volume :-

          Normal volume of blood in Adult is 5 ltr.

3. Reaction and PH :-

          Blood is slightly alkaline and PH is 7.4

4. Specific Gravity :-

          Normal value is 1.055-1.060.

5. Viscosity :-

          Blood is viscous in nature.

COMPOSITION OF BLOOD :-

          Blood contain blood cells which are called formed element and liquid portion called plasma.

PLASMA :-

          It is a straw coloured clear liquid part of blood. It contain 91-92% of water and 8-9% of solid.

Serum :-

          It is a clear straw coloured fluid that is left after the blood has clotted.

          Serum = Plasma - Fibrinogen (plasma protein)

RBC (RED BLOOD CELL) :-

1.       It is also known as Erythrocytes.

2.       RBC are non-nucleated formed elements in the blood.

3.       The Red coloured of RBC is due to the presence of the coloring pigment called Haemoglobin (Hb).

4.       The normal value of RBC is 4.5-5.0 million per cubic mm.

5.       Morphology :-

i.        The Erythrocytes are disc shaped and Biconcave (Dumbbell shape)

ii.      The center portion is thinner whereas periphery is thicker.

Thickness of center portion of cell is 1micron and thickness of periphery portion is 2.2 micron.

Diameter of blood cell is 5.5-8.8 micron.

6. Advantage :-

          Because of its Biconcave, why passing through minute capillaries RBC squeeze through capillaries without getting damaged.

Erythropoiesis :-

          It is the process of origin, development and maturation of erythrocyte.

In born babies, children and adults RBC are produced only from the red bone marrow.

1. Up to age of 20 years RBC are produced from the red bone marrow.

2. After the age of 20 yrs RBC are produced from membranous bone. eg- vertebra, sternum, ribs, scapula, iliac bones.

3. In adults RBC are produced from liver and spleen.

Note -

          Formation of RBC and WBC -

75% of WBC and 25% of RBC are formed in Bone marrow. It is due to its life spam.

Haemopoietic stem cell (HSC) :-

          It is a primary cell which are capable of self renewal which differentiate into specialized cell.

HSC are the primitive cells in bone marrow which give rise to blood cells.

CFU - colony forming unit

Function of RBC :-

1. Transport of oxygen from lungs to the tissue.

2. Transport of carbon dioxide from tissue to the lungs.

3. Buffering action in blood :-

          Maintain of Acid-Base balance in blood.

Haemoglobin : -

1. Haemoglobin is the iron containing coloring matter of RBC.

2. The main function of haemoglobin is to carry respiratory gases like oxygen and carbon die oxide.

3. The molecular weight of haemoglobin is 68000.

4. In normal condition in adults male 15g/dl and adult female 14.5g/dl.

Structure of Haemoglobin :-

1. Haemoglobin is a conjugated protein.

2. It consist of protein combined with a iron containing pigment.

3. The protein part is globin and the iron containing pigment is Haem.

Iron : Fe++

Porphyrin :- The pigment part is Haem and is called porphyrin. It is formed by four pyrole ring.

Globin :-    It contain four polypeptide chains. Among them two are alpha and two are beta.

ANAEMIA :-

          It is defined as a haemoglobin concentration in blood is below the lower limit of the normal range for the given age and sex of individual.

Pathophysiology :-

          Sub normal level of the haemoglobin causes lowered oxygen carrying capacity of blood.

Classification :-

1. Anaemia due to blood loss.

2. Anaemia due to impaired red cell formation.

3. Anaemia due to increased cell distruction.

1. Anaemia Due to blood loss :-

          Acute post hemorrhagic anaemia, It depend upon rate blood loss due to hemorrhage.

2. Anaemia Due to impaired RBC formation :-

          (i) Deficient Haem synthesis (Iron deficiency Anaemia)

          (ii) Deficient globin synthesis (Thalassemia)

          (iii) Aplastic Anaemia

          (iv) Vitamin B₁₂ / Folic acid deficiency (Megaloblastic anaemia)

          (v) Congenital defect (sideroblastic anaemia)

Clinical features :- (sign and symptoms)

1. Pallor - Light yellowish discoloration lower palpebral conjuctiva

2. Tachycardia - increase heart rate

3. Dyspnea in exertion - difficulty in respiration

4. Faintness

5. Giddiness

6. Headache

7. Drowsiness - easily tired

8. Numbness

(i) IRON DEFICIENCY ANAEMIA :-

          It is defined as inadequate availability of Iron for globin synthesis.

cause :

·         loss of blood.

·         Decreased intake of iron.

·         Poor absorption of iron from intestine.

Clinical feature :

1. Pallor

2. Tachycardia

3. Dyspnea in exertion

4. Giddiness

5. Headache

6. Faintness

7. Drowsiness

8. Numbness

9. Nails are brittle, spoon shaped nail (koilinochia)

10. Brittle hair

11. Yellowness of palm

(ii) Pernicious anaemia or Addisons anaemia :-

          It due to deficiency of Vitamin B₁₂. It is mainly due to atropy of the gastric mucosa. Because of auto immune distruction of parietal cell. This lead to poor absorption of Vitamin B₁₂.

Clinical feature :

1. Pallor

2. Tachycardia

3. Dyspnea in exertion

4. Faintness

5. Giddiness

6. Headache

7. Drawsiness

8. Numbness

9. Yellowish colour of skin

(iii) Megaloblastic Anaemia :-

          It is due to deficiency of another maturation factor called Folic acid.

(iv) Aplastic Anaemia :-

          It is mainly due to aplasia of bone marrow. It is mainly due to the repeated exposure of X-rays. Patient who are suffering from T.B. (Tuberculosis).

(v) Sickle cell Anaemia :-

          It is an inherited blood disorder characterized be sickle shaped RBC. It is due to abnormal haemoglobin called HbS.

          It become fragile, lead to Haemolysis. In sickle cell alpha chains are normal and beta chains are abnormal.

(vi) Sideroblastic Anaemia :-

          It comprises a group of disorder of diverse etiology in which the nucleated Erythroid precursoy in the bone marrow show characteristics ringed sideroblastic.

(vii) Thalassemia :-

          It is characterized abnormal haemoglobin synthesis ie alpha and beta chains are abnormal. In this, production of these chains become impaired or imbalance because of defective synthesis of globin geans.

  WBC - white blood cell

(i) It is also known as leucocyte.

(ii) They are colorless and nucleated formed element.

(iii) Normal count is 4000-11000 per cubic mm.

(iv) Life span of WBC is shorter ie 1-10 days.

(v) The main role of WBC is defense mechanism.

(vi) Compare to RBC, WBC are larger in size and less in number.

(vii) It protect the body from invading organism by acting like soldiers.

Classification of WBC :-

          WBC have granules in the cytoplasm based on presence or absence of granules in the cytoplasm WBC are divided into two part -

1. Granulocyte

2. Agranulocyte

1. Granulocyte :-

          This type of WBC have granules in the cytoplasm. They have multilobed nucleus or bilobed nucleus.

(i) Neutrophil :-

          Neutrophil is also known as polymorph. They have fine or small granules in the cytoplasm. The neutrophil is multilobed. The number of lobes in the nucleus is depend upon age of cells. Nucleus has 2-5 lobes. The diameter of the cell is 10-12 micron.

(ii) Eosinophil :-

          It has coarse granules. Nucleus is bilobed and spectacle shaped. The diameter of the cell is 10-14 micron.

(iii) Basophil :-

          It also have coarse granules in the cytoplasm. The diameter of the cell is 8-10 micron.

2. Agranulocyte :-

          This type of WBC do not have granules but have single nucleus which is not lobed.

(i) Monocyte :-

          They are the largest leucocytes. The diameter of this cell is 14-18 micron. The cytoplasm is clear ie without granules.

•       They are largest leucocytes.

•       The diameter of this cell is 14-18 micron.

•       The cytoplasm is clear ie without granules.

•       Nucleus is round, oval shape.

•       The nucleus is placed either in the center of the cell or pushed towards one side.

(ii) Lymphocyte :-

•       It also do not have granules in the cytoplasm.

•       Nucleus is oval or bean shaped.

•       Depend upon size lymphocytes are divided into two parts -
smaller and younger

•       Depend upon function lymphocyte are divided into two types-

FUNCTION OF WBC :-

1. It gives protection against infection. This is done by neutrophil and monocytes which engulf the bacteria by the process known as phagocytosis.

2. It aid in the repair of injured tissue.

3. To produce immune substance which defense against disease.

DISEASE OF LEUCOCYTES :-

          The important abnormalities of WBC are -

1. Leucocytosis

2. Leucopenia

3. Leukaemia

4. Eosinophilia

1. Leucocytosis :-

          Leucocytosis is the increase in total leucocyte count.

          It occurs in condition such as -

(i) Infection

(ii) Allergy

(iii) Common cold

(iv) TB

(v) Glandular

(vi) Pyogenic infection

(vii) Myeloid leukaemia

(viii) Myocardial infraction (MI)

(ix) Acute hemorrhage

(x) Malignancy of liver and intestine

 Pyogenic infection

          Infection characterized by severe local inflammation, especially with pus formation.

(Inflammation is defined as the local response of a living mammalium vascular tissue to injury due to any agent.)

ex :-

1. Boil/furuncle/Abscess-(staphylococcal and streptococci bacteria)

2. Tonsillitis

  Myeloid leukaemia

          Myeloid leukaemia is a type of cancer of blood and bone marrow that affects immature blood cell growth.

   Myocardial infraction

          The information of blood clot (thrombus) in the coronary artery which obstruct the flow of blood to the heart, it result in the death (infraction) of part of a heart muscle.

   Acute hemorrhage

          It is the escape of blood from blood vessel. It may be externally or internally. When the blood loss is large and sudden onset small repeated blood may occur over a period of time is known as chronic hemorrhage.

Ex - 1. Epistaxis - bleeding from nose

          2. Haematemesis - blood with vomiting

2. Leucopenia :-

          It is an decrease in total leucocyte count (TLC) below the normal limit ie 4000/mm³ of blood. It occurs in-

(i) Bacterial, viral, protozoal infection

(ii) Aplastic anemia

(iii) Malignant lymphoma

(iv) Multiple myeloma

3. Leukaemia :-

          It is a malignant disorder of haemopoeitic cell. Here the normal cell bone marrow is replaced by malignant cell. So, there is abnormal increased in the production of leucocytes. . This lead to increase in WBC count.

(i) The factor which can induce leukaemia are -

(a) Radiation specially X-rays.

(b) Chemical like benzene.

(c) Drug used for the treatment of cancer virus.

(d) Genetic disorder. eg- Down syndrome (chromosomal defect)

4. Eosinophilia :-

          It is a increase in number of eosinophils. It is mostly increase in allergic disorder like asthma, skin disorder (dermititis) and drug allergy. Also it occur in hook worm, round worm, tape worm.

Lymphocytes :-

          When the absolute count of lymphocytes is less than 1.5x10⁶/ml the condition is called lymphopenia.

It is associated with the following condition -

1. Administration of ACTH (adreno-cortico trophic harmone)

2. Advance hodgkin's lymphoma

3. Excessive radiation

Leukaemia :-

          the two leukaemia involving lymphocytes are -

(i) ALL - Acute lymphoblastic leukaemia

(ii) CLL - Chronic lymphoblatic leukaemia

(i) ALL :- (Acute lymphoblastic leukaemia)

          It is characterized by the presence of large number of immature cell or blast cell. Immature lymphocytes are called lymphoblast. It occurs in childhood.

(ii) CLL :- (Chronic lymphoblastic leukaemia)

          They are malignant lymphocytes. They manifest in the form of tumour of lymphoid tissue anywhere in the body especially in the lymphnodes. The two major type of lymphomas are -

(a) Hodgkin's lymphoma (HL)

(b) Non-Hodgkin's lymphoma (NHL)

(a) Hodgkin's lymphoma (HL) :-

•       It is a tumour of lymphoid tissue.

•       It mostly occur in young adults around the age of 32 years.

•       This tumour is associated with systemic manifestation.

•       It is characterized by the presence of special type of cell called Reed-Sternberg cell in the lymphnodes.

•       Investigation - biopsy

•       Reed-sternberg cell have two nucleus which are the mirror image of each other.

(b) Non-Hodgkin's lymphoma (NHL) :-

•       It is also a tumour of lymphoid tissue.

•       It occurs in the form of localized or generalized lymphadenopathy (inflammation of lymphnodes).

•       It has tendency to spread from one lymphnode to the other.

•       In few cources it spread to the liver, spleen, bone marrow.

•       Atlast the malignant cell spill over the blood this may create the picture leukaemia.



PLATELETS

          Platelets or thrombocytes are the formed elements of the blood.

Platelets are small, colorless, non-nucleated cell. These formed elements of the blood are consider to be the fragments of the cytoplasm. The diameter of platelets is 2.5 micron.

Platelets have several shapes like spherical, rod shape and become oval or disc shaped when inactivated. Normal count of platelets 1.5-5 lakh per cubic mm.

Properties of Platelets:-

1.    Adhesiveness

2.    Aggregation

3.    Agglutination

1.ADHESIVENESS:-

          It has the property of sticking to a rough surface while coming in contact with any rough surface the platelets are activated and stick to the surface.

2.AGGREGATION (grouping of platelets):-

          Aggregation is the grouping of platelets. Activated platelets group together and become sticky.

3.AGGLUTINATION:-

          It is the clumping togetherness of platelets.

Function of platelets:-

·       Role in blood clotting.

·       Role in clot retraction.

·       Role in prevention of blood loss.

·       Role in repair of rupture blood vessel.

·       Role in defense mechanism.

Life span and fate of platelets:-

          Average life span of platelets is 10 days. Platelets are destroy by tissue macrophages system in spleen.

Applied physiology:-

          The bleeding disorder are of three types-

1.    Hemophilia

2.    Purpura

3.    Von-willebrant disease


HEMOPHILIA

          It is a blood disorder feature by prolonged clotting time. It usually effect male and female are usually carries. Even a mild trauma, cause excess bleeding.

Clinical feature:-

          Patient of hemophilia suffers from bleeding for hour or day after the injury.

 ESR (Erythrocyte sedimentation rate)

          The rate at which erythrocyte sediments is known as ESR.

Normally in male and female ESR is 5-50 mm per hour and 5-20mm per hour respectively.

It is generally increase in Anemia, fever, rheumatoid arthritis, Acute myocardial infraction, Chronic pulmonary disease, Tuberculosis.

ESR decrease in congestive heart failure (CHF), Polycythemia.