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Respiration and Circulation — BIOLOGY STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYRespiration and Circulation4 Marks
Question
Distinguish between : Erythrocytes and Leucocytes.
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Answer

ErythrocytesLeucocytes
1. Erythrocytes have a definite shape which is elliptical or oval.1. Leucocytes do not have definite shape as they are amoeboid.
2. They are enucleated.2. They are nucleated.
3. Erythrocytes contain haemoglobin and hence appear red.3. Leucocytes are devoid of any respiratory pigment and hence appear colourless.
4. The normal erythrocyte count is 4.3 to 5.8 million per cubic mm of blood.4. The normal leucocyte count is 4000 to 11000 per cubic mm of blood.
5. The life span of erythrocytes is 100 to 120 days.5. The life span of leucocytes is 3 to 4 days.
6. The diameter of erythrocytes is 7.2 m and thickness is about 2 to 2.2 m.6. The size of leucocytes varies with its subtypes and is of average size of 8 to 15 m.
7. Erythrocytes are formed by the process of erythropoiesis in red bone marrow.7. Leucocytes are formed by the process of leucopoiesis in bone marrow, tonsils, lymph nodes, spleen, thymus, etc.
8. Erythrocytes transport the respiratory gases.8. Leucocytes help in the formation of antibodies besides fighting against foreign antigens by phagocytic activity.

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