1. Neutrophil and eosinophil structures and activities. A. Neutrophil
Neutrophil and eosinophil structures and activities. A. Neutrophil. Four nuclear lobes are visible. The cytoplasm has a faint texture, but the numerous primary and secondary granules are not readily apparent. B. Neutrophil responses to infection. Macrophages at the site of an infection secrete chemokines, which activate integrins in neutrophils, resulting in binding and diapedesis. Once in connective tissue, neutrophils follow substances released by bacteria and damaged tissue to their source and then phagocytose and destroy bacteria and damaged cells. C. Eosinophil. The eosinophilic secondary granules are readily apparent and do not obscure the nuclear lobes. (A and C, Wright stain) D. Eosinophilic attack on a parasitic worm. When eosinophils are stimulated by cytokines, they express high-affinity receptors for the IgE class of antibodies. When an invading parasite is coated with these antibodies, eosinophils will bind and release the cytotoxic contents of their granules without the requirement of phagocytosis. This extracellular release allows eosinophils to kill large invaders.
Source: BLOOD AND HEMATOPOIESIS, The Big Picture: Histology
Citation: Ash R, Morton DA, Scott SA. The Big Picture: Histology; 2017 Available at: Accessed: October 22, 2017
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