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Question 345
Physiology → Haematology
Classification
Question
SSBAQuestion Header
A circulating granulocyte engulfs bacteria and subsequently kills and digests the organisms.
Question Stem
Which intracellular combination is principally associated with this activity?
Options
A
Granule enzymes and toxic oxygen metabolites
B
Histamine and heparin
C
Interleukin-4 and platelet-activating factor
D
Actin and myosin microfilaments
E
Immunoglobulins produced by ribosomes
Explanation
Neutrophil granules contain enzymes that, together with toxic oxygen metabolites, kill and digest engulfed bacteria. Actin and myosin microfilaments account for amoeboid motility rather than bacterial killing.
Option Validity
B) Histamine and heparin are contained within basophilic granules rather than forming the neutrophil bacterial-killing system.
C) Interleukin-4 and platelet-activating factor are released by eosinophils and are not the described neutrophil bactericidal combination.
D) Actin and myosin microfilaments are responsible for amoeboid motility of neutrophils rather than killing engulfed bacteria.
E) Immunoglobulins are made by ribosomes in lymphocytes and are not the granule mechanism used by neutrophils to kill engulfed bacteria.
Further Reading
Saxena. Textbook for MRCOG-1. Physiology - Haematology - Neutrophils, p.69.