Diseases of the adrenal gland and the adrenal cortex
Endocrinology / / August 12, 2017
Blood supply of the adrenal Adrenal
provided with extremely rich blood from several arteries.To him fit the lower branches diaphragmatic artery, renal, celiac artery, the branches coming directly from the aorta.From these arteries depart thin vascular branches in the amount of about 50 to each adrenal gland, which penetrate from all sides into the capsule of the adrenal gland, and its rear surface provided with a large number of vessels than the front.The capsule artery anastomoziruya with each other, branch out and form a dense network, from which depart two kinds of vessels.Some so-called perforating, penetrate, not a branch, in the medulla, which fall into a sine wave located between the groups of cells.Other vessels that penetrate into the cortex of the adrenal gland, pass between the last cell strands and extending, end sinusoids.Sinusoidal endothelium of the adrenal cortex is closely associated with parenchymal cells.
capillary network of the cortex becomes veins that flow into the inferior ven
Occasionally bark capillaries anastomose with the capillaries of the brain substance.In general, the blood supply to the cortex and medulla of the adrenal gland is a separate vascular system.
The medulla venules and veins make up the vasculature.Venous capillaries, starting blindly between the cells of the beam zone, give rise to the central vein.Consequently, the arterial capillaries of the adrenal cortex does not go directly into the venous capillaries of the brain substance;among them are the cells of the cortex to secrete hormones that are released by the adrenal glands through a central vein.
feature central vein structure is present in the wall of it, besides the usual thin, circularly arranged muscle layer, powerful, longitudinally extending bundles of smooth muscle fibers.Coming through the hilus to the surface of the prostate as the adrenal vein, the left central Vienna falls into the corresponding renal vein and the right - the inferior vena cava.There is an assumption that central vein muscle bundles control the amount of blood, and hence the amount of oxygen required for gidroksilyatsii steroid hormones.
Lymphatic adrenal system richly developed.Lymphatic vessels begin in the medulla and passing radially through the crust, forming a dense network of closely entwine group cortex and medulla cells.This is particularly dense capillary network in the network area of the cortex.Coming out of the adrenal glands, lymphatic vessels are sent to the regional lymph nodes.
innervation of the adrenal
innervation of the adrenal glands is carried out by the branches of the celiac plexus (plexus coeliacus), adrenal plexus (plexus suprarenalis), renal plexus (plexus renalis) and branches of large splanchnic nerve (n. Splanchnicus major).In addition, the adrenal glands get even the lower branches of the phrenic plexus (plexus phrenicus inferior).According to research large splanchnic nerve contains secretory nerve fibers to the adrenal gland, which is part of the preganglionic.Postganglionic fibers terminate on epithelial cells of the adrenal medulla as a nerve endings.
The capsule of the adrenal gland located in a large number of different thickness and length of the nerve trunks.In the interior of the capsule, on the border with glomerular area, located quite thick, krupnopetlistoe plexus, which runs the nerve trunks that penetrate the bark and smack on his way nerve branches to the cortex.After passing through the crust, these nerve trunks to form medulla dense plexus, which runs thin, usually non-fleshy nerve fibers that form at the end of the secretory cells of the brain substance.
As in the cortex, and there are receptor endings, especially numerous in the brain in the medulla of the adrenal glands.
in the adrenal glands, mainly in the medulla, there are nerve cells that are concentrated mainly around the large veins.They lie singly or in groups of 8/12/30 cells (mikroganglii), occasionally it is possible to see up to 90-100 cells in one section of the adrenal gland.Dimensions of nerve cells mostly large.Their form is round or angular, chromatophilic protoplasm contains a substance, usually a network structure.Often in the protoplasm of these cells can be seen a dark-brown pigment.Big bubble-core is usually in the center of the cell.Almost each adrenal gland can be observed a certain number of nerve cells in the process of destruction: spherical bulge at the ends of shoots, the disappearance of neurofibrillary, pycnosis nuclei.
adrenal cortex has a high regenerative capacity, but the localization of these processes still remains controversial.
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Glomerular zone is considered by some researchers as the germinal (cambium) layer, whose cells give rise to the cellular elements of the other cortical areas.
Zwemer and others expressed the view that the progenitor cells of all layers of the cortex is a capsule, which cells migrate to the center and reach the end zone of the mesh, where the die ( «escalator theory») in 1938.
In 1942, there is the theory of "fields of transformation of the adrenal cortex» Tonutti, who believes that the cortical cells can move under the influence of a variety of reasons from rest to a state of enhanced reproduction.At the center of these processes is beam zone, especially its outer part, the richest mitosis.Inwards and outwards from this zone occurs cortex growth, t. E. The conversion of glomerular cells and mesh zones in the beam zone cells.With the progression of the process of disappearing morphological differences of the transformation of the field is lost zonal structure of the cortex.
According to Symington, labile fetal cortex cells exhibit active division mainly in its peripheral areas.The adrenal cortex cells of adult stable, minimal mitotic activity, mainly in compact cells netted area.Partial resection of adrenal cells in the subcapsular region acquire properties labile cells and regeneration goes on fetal type.
Experimental studies with autologous adrenal conducted IM Shapiro in 1954, EI Tarakanov in 1958, VK Kulagin and DY Shurygin in 1960, showed that the regeneration of the adrenal cortex is due to subcapsular layers of cells.The study revealed the formation of new cells in the cortex of the adrenal capsule in the subcapsular and glomerular areas.Upon stimulation of the adrenal cortex ACTH regeneration processes occur in all areas of the cortex, mainly due to the undifferentiated cells, which penetrate the capsule and glomerular zone Beam and mesh layers are initial elements for the formation of new cells.
12 Aug, 2017
12 Aug, 2017