List of abbreviations		 Vocabulary
of micros-
copic
anatomy
specialist terms
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German

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Editor:
Dr. med.
H. Jastrow
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Overview eosinophil granulocytes (Granulocyti acidophili; Eosinophili):
Pages with explanations are linked to the text below the images if available! (Labelling is in German)
eosinophil granulocyte
(human newborn)		 detail 1: cytoplasma +
vesicles		 detail 2: cytoplasma +
vesicles (human)		 detail 3: light crystals in
vesicles (human)		 detail 4: light
crystal (human)		 detail 5: barely visible
crystal (human)		 detail 6: dark crystals
(human)		 detail 7: dark
crystal (human)
detail 8: dark crystal
(human)		 detail 7: heterolyso
some + crystals (human)		 young eosinophil
(umbilical artery, human)		 central detail: cytoplasm
(human)		 detail 1: vesicles with
crystals (human)		 detail 2: vesicles with barely
visible crystals (human)		 detail 3: idem (human)
eosinophil in connec-
tive tissue (rat)		 vesicle with barely visible
crystal (rat)		 detail thereof: vesicles
with light crystals (rat)		 eosinophil in a
capillary (rat)		 vesicles with dark
crystals (rat)		 eosinophilic and baso-
philic granulocyt (rat)		 eosinophilic granulo-
cyte in epithelium (rat)		 detail thereof: cytoplasm
 ileum (rat)
Eo in vaginal connec-
tive tissue (pig)		 Detail 1: vesicles Detail 2: nice
crystal
Eosinophilic granulocytes or eosonophils (Terminologia histologica: Granulocyti acidophili; Eosinophili)  belong to the white blood cells (leucocytes). They are characterised by special primary lysosomes with diameters of 0.5 to 1.5 µm in which a special basic protein (major basic protein; which is also called the internum) forms crystals. These crystals can be identified by a very regular pattern of electron-dense stripes that have a constant distance of about 3nm in very high resolutions. The varying electron-dense or -lucent appearance of the crystals in the surrounding vesicle content (externum) that also varies in electron density most robably is due to pH and protein concentration. As can be seen in the images there are very dense crystals in moderate electron-dense vesicles or rather electron dense vesicles with electron-lucent crystals. The externum contains peroxidase and other enzymes. The name eosinophils derives from the intense red stain of the primary lysosomes by eosin (an acid staining agend) in light microscopy. Eosinophils have small pseudopods, i.e. they may migrate through tissues. Further they belong to the microphages and thus are able to phagocyte larger particles. It is assumed that they primaryly incorporate and digest foreign proteins. There are about 1-4% eosinophils in white blood count. Their relative number rises considerably in case of parasite infections, especially in case of worm deseases, scarlet and allergic asthma (eosinophilia) and it decays in case of measels and thyphus (eosinopenia). Eosinophils are attracted by a factor released by basophilic granulocytes and mast cells in case of inflammatory reactions where they are supposed to reduce local histamine effects. Whereas most eosinophils are seen in blood, they may also invade epithelia of the skin and mucosa of the respiratory or intestinal tract. However, more often they migate as free cells through mainly loose connective tissue. Their defense of parasites involves exocytosis of whole primary lysosomes that after disruption set their content free, especially the major basic protein. Eosinophils are phagocyted by macrophages and during their degradation inside large phagolysosomes the macrophages show typical Charcot-Leyden crystals consisting of lysophospholipase.

--> Blood cells, neutrophilic granulocytes, basophilic granulocytes, blood vessels, connective tissue
--> Electron microscopic atlas Overview
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