The parathyroid gland

The parathyroid gland (synonym: epithelial bullock, parathyroid gland, parathyroid gland) - the glands that produce parathyroid hormone, parathormone (see Hormones). The parathyroid glands are located behind the lateral lobes of the thyroid gland in the form of brown-red tapered grains, usually two on each side (Fig). Perhaps atypical location of the parathyroid glands in the neck. The value of the parathyroid gland about 6 X 4 2 mm
Parathyroid glands consist of a mass of glandular epithelial cells that are grouped into bands or lobules, which are separated by a thin connective tissue walls. Secretory process takes place continuously. Connective tissue layer start capsules and passing vessels and nerves. Blood to the gland is supplied along the branches of the inferior thyroid artery. The extensive network of capillaries obletaet columns of cells and the alveoli. The blood flowing going in subcapsular veins, which come to the surface of the parathyroid glands and fall into the nearby Vienna. They are innervated by the parathyroid gland cervical sympathetic Department of the trunk and the vagus nerve.
The parathyroid glands are involved in regulation of the exchange of calcium and phosphorus. Destruction of glands followed by a drop in the calcium concentration in the serum. Violation function of the parathyroid glands and the related changes in the level of parathormone causes a change in the concentration of calcium ions in the blood and leads to the development of a number of diseases - hyperparathyroidism, leading to increased levels of calcium and reduction of phosphorus in the blood, and hypoparathyroidism (see Tetany).

the parathyroid gland person Fig. 1. The parathyroid gland person, appearance (right side) and topography:
1 - lingua (language);
2 - gl. submandibularis;
3 - a. lingualis;
4 - a. thyreoidea sup.;
5 - v. thyreoideae sup. (BNA);
6 - a. carotis int.;
7 - rr. glandulares;
8 - v. jugularis int.;
9 - a. carotis comm.;
10 - gl. Thyreoidea (thyroid gland);
11 - v. thyreoidea inf.;
12 - a. thyreoidea inf.;
13 - trachea;
14 - n. laryngeus recurrens;
15 - esophagus (gullet);
16 - r. oesopliagei;
17 - gl. parathyroidea inf. (the bottom of the parathyroid gland);
18 - n. laryngeus inf.;
19 - gl. parathyroidea sup. (the top of the parathyroid gland);
20 - r. pharyngeus:
21 - plexus pharyngeus;
22 - pharynx;
23 - v. pharyngeal;
24 - a. carotis ext.;
25 - palatum molle.

The parathyroid gland (glandulae parathyreoideae; synonym: epithelial bullock, parathyroid gland, parathyroid gland) - gland of internal secretion, belonging to the group bronhogenny (gr. branchia - gills, genos - origin), i.e. glands, emerging from Gill pockets of the pharyngeal gut.
Embryology. Top pair O. W. going from outgrowths of the dorsal-cranial region IV pair Gill pockets; the bottom of the pair III Gill pockets, outgrowths which are shifted in caudal direction.
Anatomy and histology. Formed O. W. localized on the back surface of the thyroid gland (Fig. 1). Top pair them lies behind the ascending line of the inferior thyroid artery and the recurrent laryngeal nerve in the medial edge of the thyroid gland at the level of the lower edge of the cricoid cartilage. Bottom pair O. W. usually located at the lower end of the side lobes of the thyroid gland, or at the upper end of the thymus gland in front of the inferior thyroid artery. There are various individual variations of topography O. W. The weight of each O. W. on average 35-40 mg
The parathyroid gland richly supplied with blood mainly from special branches of the inferior thyroid artery. Entering the gates of O. J., artery forms a network of capillaries, which gathers in the bottom of the capsule venous network. Vienna O. W. fall into the veins of the thyroid gland, trachea and esophagus.
Sympathetic innervation of O. J. receive from the upper and lower cervical and stellate ganglion of the respective party; parasympathetic from wandering nerves. But terminal branches of the nerve fibers that form loops and points between glandular cells, O. W. described terminal devices sympathetic fibers in the form of baskets around oxyphilic cells. Sensitive innervation of O. J. is the fibers of neurons system vagus nerve; the bodies of nerve cells lie in ganglion nodosum the party concerned.
Each of the parathyroid gland is covered outside of connective tissue capsule. The internal structure of the parathyroid glands varies mainly depending on age: children prevails compact location glandular cells of O. J.; the boys bands cells O. W. are in the form of pillars or networks, separated by connective tissue; in Mature and old age due to thickening of the tissue layers O. W. are split up into slices of various sizes. Among glandular elements of O. J. the most numerous so-called master cells, which are small, light homogeneous cytoplasm and large puzirkoviy kernel. In the cytoplasm of the principal cells contain the inclusion of glycogen and fat.
On the periphery of O. J. are bands or small clusters of oxyphilic cells that differ from the main greater magnitude and content in the cytoplasm of the numerous small oxyphilic granules. Kernel oxyphilic cells compact; in the cytoplasm, as a rule, there is no inclusion of glycogen and fat. Oxytelinae cells appear in the O. J. after 4,5-7 years; in the future their number is growing. Between these two main types of cells O. W. meet transitional forms ("dark master cells"). The most likely producer hormone O. W. are master cells; oxytelinae cells usually considered as an aging elements. "Dark master cells", apparently, is a transition stage between them, but at excitation of activity of O. J. may be activated and to become a normal bright master cells. Often O. W. formed follicle-like structures, filled like a colloid mass and reminiscent of the thyroid follicles. However, in the content of these structures iodine is missing, and most likely they are testopodobnymi entities, arising out of delay in issuing the hormone O. W. Cm. also Glands of internal secretion.