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Leukocyte Function: Learning Objectives

Medical Importance

Host defense depends on specialized blood cells that identify foreign micro-organisms/molecules and utilize oxidants, proteases, and other moieties to protect the host. A deficiency in number or qualitative function of leukocytes can lead to overwhelming infection. Excess activation of the leukocytes can lead to inflammatory tissue injury.


  1. Compare and contrast the morphology, cytoplasmic contents and functions of neutrophils, monocytes, eosinophils, and basophils.
  2. Describe the normal function of neutrophils and monocytes/macrophages, including chemotaxis, phagocytosis, and killing and digestion of foreign materials.
  3. Describe disorders of granulocytes, including congenital neutropenia and chronic granulomatous disease.
  4. Describe the causes, clinical features, and treatment principles of neutropenia.
  5. List the differential diagnosis for neutrophil leukocytosis and to define the phrase "left shift".
  6. Define the leukemoid reaction and list specific causes of this phenomenon.
  7. List the differential diagnosis for eosinophilia.