PRACTICAL

OPTIONAL PRACTICAL WORK

TOPIC: PREPARATION OF BLOOD SMEAR AND STUDY OF BLOOD CELLS OF MAN.

INTRODUCTION :

Blood is a specialized fluid connective tissue which acts as the main transporting system of the body. Plasma is the liquid component constitutes about 55% of the total blood volume and consists of 91.5% of water and 8.5% of solutes. Cellular components include erythrocytes, leucocytes, and platelets. The  myeloid tissue produces Erythrocytes, Granular leucocyte , thrombocyte and platelets. While Agranular leucocytes are produced by both by myeloid and lymphoid tissue. Red blood corpuscles have a biconcave disc shaped structure.  Haemoglobin gives  red color to the  RBCs and hence the blood is red in color. The Erythrocytes are non-nucleated and are more in number.Human blood has an average number 4.8-5.4 million Erythrocytes is about 120 days.The old and worn out erythrocytes are destroyed in the spleen and liver. The primary function of erythrocytes is transportation of respiratory gases and regulation of PH of blood .The white blood corpuscles are nucleated and are less in number. The nuclei are variously shape.  Leucocytes ranges from 7000-10,000 cells/mm³ of blood. White blood corpuscles are of five types namely Neutrophils, Eusinophils ,Basophils, Monocyte and Lymphocytes. The leucocytes play a vital role in protecting the body against invading bacteria , viruses , fungi and parasites by a process called phagocytosis and also produce antibodies thus involving in the body’s immune system. Their lifespan ranges from 3-12 days.

                                   Blood platelets are also called thrombocytes , They are the smallest of the blood cells and are non nucleated, round/oval discs ranging from 2,00,000-2,50,000 cells /mm³ of blood and are involved in the process of blood clotting. Their lifespan ranges from 4-9 days.

                                   Many Diseases are caused by abnormalities in the blood.The common red blood cells diseases are anaemia and polythemia. Anaemia is a pathological  condition that effects the erythrocytes.Production area resulting in an increase of the erythrocyte cell count and viscocity of blood, which cause blockage in the blood vessels.The most important WBC disease ‘Leukemia’ or ‘Blood cancer’.This is caused by an uncontrolled over production of immature non-functional leucocytes.

AIM: To prepare a stained human blood smear and observe components.

MATERIALS REQUIRED: Sterilized needle , sterilized cotton, methylated spirit, clean glass, slides, wright’s stain ,distilled water, beaker, compound microscope etc.

PROCEDURE: Cleaned the fingertip with cotton swab wet with spirit and pricked it with a sterilized needle about 2-3 mm deep.The first drop of blood was discarded . Held the slide in hand and applied at its one end a drop of blood oozing from the finger.Placed the slide on a plane surface held a second slide between the thumb and index finger inclined over the first slide at an angle of 45⁰ infront of the drop of blood in the first slide. The second slide was moved slowly without exerting any pressure  on the first slide to spread the blood into a thin , uniform layer over the slide. The first slide was air dried for a minute. After drying, wright’s stain was poured over the entire blood smear and kept aside for nearly 2-4 minutes. The slide was washed repeatedly for sometimes in distilled water  and was examined under high power  of the compound microscope to study the detailed morphology of the blood cells .  

OBSERVATION:

ERYTHROCYTES:  

Numerous, small, biconcave, disc shaped, non-nucleated erythrocytes was seen.

LEUCOCYTES:  

 Leucocytes were larger , nucleated cells and were lesser in number compared to erythrocytes . Based on the presence or absence of granules in the cytoplasm , the leucocytes were of two types namely granulocytes and agranulocytes.

GRANULOCYTES;

1.   Neutrophil: It constitutes 60-70% of the total leucocyte and had a cell size if 8-10 microns.Nucleus is bilobed .

2.   EUSINOPHIL: It constitutes 2-4% of the total number of leucocytes and had the cell size of 10-12 microns.Nucleus is bilobed.

3.   BASOPHIL:  Basophil constituted 0.5- 1% of the  total number of leucocytes and had a cell  size of  8-10m. Nucleus  is  bilobed .

AGRANULOCYTES

     Agranulocytes   lacked  granules   in  the  cytoplasm  and were of  two       types  namely  lymphocyte  and monocyte.

1.    Monocyte:   Monocyte constituted  3- 8% of the total leucocytes. They  were largest  among the leucocytes and had a cell size of 15-20m. The nucleus was kidney/bean horse shoe  shaped. The cytoplasm stained   pale blue colour and  had a foamy appearance.

2.    Lymphocyte:  Lymphocytes constituted 25% of the   total leucocytes. They were the smallest among the leucocyte and had a cell size of 7- 15m. The nucleus was round and the cytoplasm had a hazy appearance.

RESULT

The  stained  human blood smear  showed numerous non- nucleated erythrocytes, and different types of leucocytes( Granulocytes &  Agranulocytes)

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