MCQ – 89373

Identify the cells marked in the image.

1. Lymphocyte
2. Monocyte
3. Eosinophils
4. Basophils

A.	A-2; B-3; C-1; D-4
B.	A-1; B-4; C-2; D-3
C.	A-3; B-2; C-4; D-1
D.	A-4; B-1; C-3; D-2

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Correct Answer » A Explanation

Monocytes: Largest leukocytes with kidney-shaped or folded nuclei; cytoplasm is abundant and grayish-blue.
– Eosinophils: Characterized by bilobed nuclei and large orange-red granules in cytoplasm.
– Lymphocytes: Smaller cells with large, round, dark-staining nucleus; scant pale cytoplasm.
– Basophils: Contain large, dark purple or black granules that often obscure the nucleus.

Monocytes: Largest, kidney-shaped nucleus, precursor to macrophages.
– Eosinophils: Bilobed nucleus, orange-red granules, fight parasites, allergic reactions.
– Lymphocytes: Round nucleus, scant cytoplasm, key in adaptive immunity.
– Basophils: Dark purple granules, mediate hypersensitivity reactions by releasing histamine.

– Morphological Identification
– Size and nucleus shape are key in differentiating leukocytes.
– Cytoplasmic granules’ color and size identify granulocytes (eosinophils, basophils, neutrophils).
– Agranulocytes (lymphocytes, monocytes) differ by nucleus morphology and cytoplasm amount.

– Clinical Relevance
– Monocytes increase in chronic infections and inflammation.
– Eosinophils rise in parasitic infections and allergies.
– Basophils are rare but important in allergy and anaphylaxis.
– Lymphocytes increase in viral infections and some leukemias.