Step 1: Analyze the given options and identify the cell types
The image displays diagrams of different white blood cells (leukocytes) along with their typical percentages in the blood and their primary functions. We need to identify the correct match among the given options.
(a) Eosinophil: The image shows a cell with a bilobed nucleus and prominent granules. This morphology is characteristic of an eosinophil.
(b) Basophil: The image shows a cell with a lobed nucleus often obscured by large, dark-staining granules. This is characteristic of a basophil.
(c) Neutrophil: The image shows a cell with a multi-lobed nucleus. This is characteristic of a neutrophil.
(d) Monocyte: The image shows a large cell with a kidney-shaped or horseshoe-shaped nucleus. This is characteristic of a monocyte.
Step 2: Evaluate the percentage and function for each cell type
(a) Eosinophil: Eosinophils typically constitute 2-4% of total white blood cells and are primarily involved in defense against parasites and allergic reactions, not phagocytosis as their main function.
(b) Basophil: Basophils are the least numerous white blood cells, making up 0.5-1.0% of the total. They contain granules that release histamine and serotonin during allergic and inflammatory responses.
(c) Neutrophil: Neutrophils are the most abundant white blood cells, making up 60-70% of the total. Their primary function is phagocytosis of bacteria and other pathogens.
(d) Monocyte: Monocytes constitute 3-8% of total white blood cells and differentiate into macrophages, which are highly phagocytic and involved in antigen presentation and removal of cellular debris, not primarily allergic reactions.
Step 3: Determine the correct match
Based on the analysis in Step 2, option (b) correctly matches the basophil's structure, percentage (0.5-1.0%), and function (secreting histamine and serotonin).
Answer:
The correct match is (b) because basophils, which make up 0.5-1.0% of white blood cells, are responsible for secreting histamine and serotonin, key mediators in allergic and inflammatory responses.