[Comparative evaluation of age-related and organic characteristics of the structure of the adventitial nerve plexuses in human arteries].

It has been stated by means of morphometric investigation of transversal sections of the nervous-vascular complexes of the thyroid, splenic and brachial arteries, stained after Weighert-Pahl, that in the human being during the first mature period the amount of nerves in adventitia of nervous arteries is 1.4-2.7 times greater than in the newborn, and in the old man--1.3-1.6 times less than in the mature person. Average total area of the nervous transversal sections changes in the same proportion with age. The age factor is the leading cause in increasing amount of nerves and the total area of their sections at the stage of productive development of the plexuses, as well as in decreasing of these indices in ageing process. In each age group the amount of nerves is proportional to the diameter of the artery lumen and to the organ's mass (spleen). The greatest amount of nerves at all stages of human development occurs in the adventitial plexuses of the thyroid arteries; they are less numerous in the plexus of the splenic artery, and their minimal amount is noted in the plexus of the brachial artery. Most of the nerves in adventitia of the arteries have microscopical diameter (less than 70 mcm), serve for selective, discrete innervation of the arterial wall.