Paraganglion

Paraganglion of the gallbladder

Paraganglia are process-less, secretory active (neuroendocrine) cells without nervous functions. In ontogenesis (development process of an individual living being) they arise from sympathicoblasts , cells from which the typical nerve cells of the sympathetic nerve are also formed. The sympathicoblasts migrate out of the neural crest and are therefore of ectodermal origin.

Paraganglia consist of epithelial-like parenchymal cells and a vascularized interstitium and are surrounded by a connective tissue capsule. Depending on whether they can be colored with chromium salts, a distinction is made between chromaffine and non-chromaffin paraganglia. The chromaffines contain high concentrations of the catecholamines, which are colored with chromium salts . But the non-chromaffin ones also contain low concentrations of catecholamines, so that the distinction has no functional significance. The same applies to a separation of the "parasympathetic" from the "sympathetic" paraganglia; the "parasympathetic" ones are also formed from sympathicoblasts. The discoverer and namesake of the Paraganglia was the Austrian histologist Alfred Kohn , who also coined the word chromaffin .

The Paraganglia include, with inconsistent nomenclature:

• the adrenal medulla
• the carotid body in the carotid bifurcation
• the glomera aortica in front of the aortic arch
• the paraganglion tympanicum (glomus tympanicum) near the nervus tympanicus
• the jugular paraganglion (glomus jugulare) in the wall of the internal jugular vein
• the paraganglion laryngeum (glomus laryngeum) in the pocket ligament of the larynx
• the paraganglion aorticum abdominale or ( Zuckerkandl organ) on the arteria mesenterica inferior

There are also paraganglia in the genital organs and under the peritoneum .

The two glomus organs, perhaps also other paraganglia, are chemoreceptors for measuring the oxygen and carbon dioxide levels in the blood. If the oxygen and carbon dioxide content is too low, they cause breathing to increase.

Numerous in the child, the paraganglia regress later. Tumors of the paraganglia are called paraganglioma or pheochromocytoma .

literature

• Peter Böck: The Paraganglia. In: Handbook of the microscopic human anatomy. Volume VI: Blood and Lymph Vascular Apparatus , Internal Secretory Glands . Springer-Verlag , Berlin 1982, ISBN 3-540-10978-1 .
• G. Klöppel: tumors of the adrenal medulla and paraganglia . In: The Pathologist . tape 24 , 2003, pp. 280-286 , doi : 10.1007 / s00292-003-0635-8 .
• R. Lüllmann-Rauch: Histology. 3. Edition. Thieme Publishing Group , Stuttgart 2009, ISBN 978-3-13-129243-8 .

Individual evidence

1. ↑ Böck 1982.
2. ↑ Alfred Kohn: The Paraganglia. In: Archives for microscopic anatomy. 62, 1903, pp. 263-365.
3. ↑ Böck 1982.
4. ^ Julius H. Comroe : The peripheral chemoreceptors. In: Wallace O. Fenn, Hermann Rahn (Eds.): Handbook of Physiology Section 3: Respiration. Volume 1, American Physiological Society , Washington 1964, pp. 557-583.