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Question 338
Physiology → Haematology
Classification
Question
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A neutrophil retains its bactericidal granule contents but loses the cytoskeletal apparatus required for amoeboid movement. Loss of which intracellular components most directly accounts for this defect?
Question Stem
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Options
A
Histamine and heparin
B
Fibrinogen and factor XIII
C
Carbonic anhydrase and haemoglobin
D
Serotonin and calcium
E
Actin and myosin microfilaments
Explanation
Neutrophils are amoeboid cells. Their actin and myosin microfilaments are responsible for amoeboid motility, whereas their granules contain enzymes that, together with toxic oxygen metabolites, kill and digest engulfed bacteria.
Option Validity
A) Histamine and heparin are characteristic contents of basophil granules rather than the neutrophil motility apparatus.
B) Fibrinogen and factor XIII are platelet alpha-granule constituents and are not responsible for amoeboid movement.
C) Carbonic anhydrase and haemoglobin are associated with erythrocyte respiratory-gas transport rather than neutrophil motility.
D) Serotonin and calcium occur in platelet dense granules and do not constitute the neutrophil cytoskeletal apparatus.
Further Reading
Saxena R. Textbook for MRCOG-1. Chapter 3: Physiology – Haematology. p.69.