how are eosinophils formed

Eosinophil granulocyte - Wikipedia, the free encyclopedia


** Eosinophil granulocyte **

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/Eosinophil granulocyte/
Eosinophil blood smear.JPGEosinophil under the microscope (400x) from a
peripheral blood smear. Red blood cells surround the eosinophil, two
platelets at the top left corner.
Code TH /H2.
Anatomical terminology

3D Rendering of Eosinophil

*Eosinophil granulocytes*, usually called *eosinophils* or *eosinophiles*
(or, less commonly, /acidophils/), are white blood cells and one of the
immune system components responsible for combating multicellular parasites
and certain infections in vertebrates. Along with mast cells, they also
control mechanisms associated with allergy and asthma. They are
granulocytes that develop during hematopoiesis in the bone marrow before
migrating into blood.

These cells are eosinophilic or 'acid-loving' as shown by their affinity to
coal tar dyes: Normally transparent, it is this affinity that causes them
to appear brick-red after staining with eosin, a red dye, using the
Romanowsky method. The staining is concentrated in small granules within
the cellular cytoplasm, which contain many chemical mediators, such as
histamines and proteins such as eosinophil peroxidase, ribonuclease
(RNase), deoxyribonucleases, lipase, plasminogen, and major basic protein.
These mediators are released by a process called degranulation following
activation of the eosinophil, and are toxic to both parasite and host

In normal individuals, eosinophils make up about 1-6% of white blood cells,
and are about 12-17 micrometers in size.^[1] They are found in the medulla
and the junction between the cortex and medulla of the thymus, and, in the
lower gastrointestinal tract, ovary, uterus, spleen, and lymph nodes, but
not in the lung, skin, esophagus, or some other internal organs^[/vague/]
under normal conditions. The presence of eosinophils in these latter organs
is associated with disease. Eosinophils persist in the circulation for


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