ISSN:
1432-0878
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary According to the internal structure and size of the granules, six types of nerve endings can be distinguished in the toad median eminence: 1. Endings containing mostly dense granules of 600 Å in diameter; 2. Endings containing dense granules of about 800 Å in diameter; 3. Endings which contain dense granules 1,000–2,000 Å in diameter, with the peak at 1,200–1,400 Å; 4. Endings containing granules with a characteristic structure, which differentiate them from the other three types; 5. Scarce endings containing granules 2,000 to 3,800 Å in diameter; and 6. Endings containing only vesicles 400–500 Å in diameter. Types 3 and 4 endings are mainly found in the outer pericapillary zone, and are probably responsible for the strong Gomori-positive reaction observed in this zone. The other four types of endings occur mainly in the inner pericapillary zone, and appear to be Gomori-negative. The probable origins of the different types of endings, and their possible relations with the different releasing factors is discussed. The subendothelial basement membrane has numerous long processes which form a complicated network in contact with all the nerve endings, some nerve fibres and glial cells. Two types of glial cells are described. Pinocytotic vesicles are frequently seen at the points where these cells contact the basement membrane. All the ultrastructural features suggest that these cells are carrying out transport functions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00336689
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