Monday, 5 November 2012

Granulocytic cells

The granulocytes are classified as Neutrophils, Eosinophils and Basophils on the basis of cellular morphology and cytoplasmic staining characteristics.granulocytes

a) Neutrophils:

  • It has a multi-lobed nucleus & granulated cytoplasm that stains with both acid & basic dyes.
  • It is often called a "Poly-morphonuclear leukocyte'(PMN)
  • These are produced by hematopoiesis in the bone marrow, which are released into the tissues, where they have a life span of only a few days.
  • Movement of circulating neutrophils into tissues called "Extravasation".
  • The neutrophils contains primary & Secondary granules:

Larger, denser primary granules

Peroxidase, Lysozyme, Various hydrolytic enzymes

Smaller, secondary granules

Collagenase, Lactofemn & Lysozyme

  • Both primary & secondary granules are fuse with phagosomes.
  • The cells exhibit a larger "Respiratory Burst" than macrophages & express higher levels of "defensins" than macrophages do.

b) Eosinophils:

  • The cells are motile phagocytic cells that can migrate from the blood into the tissue spaces.
  • It has a bi-lobes nucleus & a granulated cytoplasm that stains with the acid dye "Eosin" red (hence its name).
  • Play a significant role like phagocytic role like macrophages.
  • The secreted contents of eosinophilic granules may damage the parasite membrane.

c) Basophils:

  • It has a lobed nucleus and heavily granulated cytoplasm that stains with the basic dye "methylene Blue".
  • These are nonophagocytic granulocytes, which release pharmacologically active substances from their cytoplasmic granules. These substances play a major role in certain "Allergic responses".

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