Free Connective Tissue Cells-Eosinophilic Granulocyte

Eosinophilic granulocytes occur not only in blood (1–4% of the leukocytes)  but also in connective tissue. Eosinophilic granulocytes measure about 12 μm in diameter. That makes them slightly larger than neutrophil cells. They have a bilobed nucleus (spectacle form). In the figure, the connection between the two lobes is not visible .  The characteristic marker for eosinophils are eosin-stain d acidophilic or eosinophilic granules. In electron microscopy, these show a remarkably regular and characteristic structure. The oval, discus-shape d granules contain a central, oblong crystalloid body, termed internum. At higher magnification, the internum reveals a lamellar structure. A layer of lesser electron density was named externum or matrix. It surrounds the crystalloid inner body. These acidophilic granules are modified lysosomes, which contain various acid hydrolases, such as acid phosphatase, cathepsin, peroxidase, arylsulfatase and ribonuclease, among others. There are few cytoplasmic organelles. Eosinophilic granulocytes recognize and phagocytose antigen-antibody complexes, and they show ameba-like mobility.

Electron microscopy; magnification: × 16400

References

Kuehnel, W.(2003). Color Atlas of Cytology, Histology, and Microscopic Anatomy. 4^th edition . Institute of Anatomy Universitätzu Luebeck Luebeck, Germany . Thieme Stuttgart · New York .