Medical Biology: Neutrophils

Neutrophils

• Constitute 60-70% of circulating leukocytes
• Nucleus consists of 2-5 lobes linked by fine chromatin thread
• Cytoplasm contains small specific granules
• Circulate in blood in resting state, but can become motile and phagocytic in tissues
• Primary function is to ingest and destroy invading organisms
• Die after performing their function, resulting in pus formation

Eosinophils

• Constitute 2-4% of total WBC count
• Have a characteristic bilobed nucleus
• Presence of many large and elongated granules that are stained by eosin
• Increase in number in parasitic infestations and allergic states
• Play a major role in protecting against parasitic diseases

Basophils

• Constitute less than 1% of total WBC count
• Nucleus is divided into irregular lobes
• Cytoplasmic granules are large, intensely basophilic, and irregular in size and shape
• Contain histamine (vasodilator) and heparin (anticoagulant)
• May be precursors of tissue mast cells

Lymphocytes

• Constitute 20-25% of WBCs
• Have an ovoid nucleus and scanty cytoplasm
• Two main types: T lymphocytes and B lymphocytes
• Responsible for immune surveillance and detecting foreign particles in tissues
• B lymphocytes can differentiate into plasma cells after immune response
• Plasma cells are responsible for active synthesis of immunoglobulins

Monocytes

• Are the largest of the leukocytes
• Constitute 3-8% of WBCs
• Have an oval or kidney-shaped nucleus and basophilic cytoplasm
• Can live in blood for 8 hours, then move into connective tissue
• Precursor cells of tissue macrophages and other cells of the mononuclear phagocytic system

Learn about neutrophils, a type of leukocyte, their structure, function and role in the immune system. Understand their circulation, activation, and phagocytic properties.