parathyroid glands


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parathyroid

 [par″ah-thi´roid]
1. near the thyroid gland.
3. a preparation containing parathyroid hormone from animal parathyroid glands; used for diagnosis and treatment of hypoparathyroidism.
parathyroid glands four small endocrine bodies in the region of the thyroid gland; they contain two types of cells: chief cells and oxyphils. Chief cells are the major source of parathyroid hormone (PTH), the secretion of which is dependent on the serum calcium level. Through a closed-loop feedback mechanism a low serum calcium level stimulates secretion of PTH; conversely, a high serum calcium level inhibits its secretion. The essential role of PTH is maintenance of a normal serum calcium level in association with vitamin D and calcitonin. It does this by exerting its effects on bone, kidney, and gastrointestinal tract. In bone, it enhances bone resorption by increasing digestion of the bone matrix by osteoclasts, which produces calcium that gets released into the bloodstream. In the kidney, PTH increases the excretion of phosphate and the reabsorption of filtered calcium. In the intestine, it increases intestinal absorption of calcium. The parathyroid glands may be subject to either hyperparathyroidism or hypoparathyroidism.

parathyroid glands

Four, yellow, bean-shaped bodies, each about 0.5 cm long, lying behind the THYROID GLAND, usually embedded in its capsule. The parathyroids secrete a hormone, parathyroid hormone (parathormone or PTH), into the blood if the level of calcium in the blood drops. This hormone promotes the release of calcium from the bones, controls loss in the urine and increases absorption from the intestine, thus correcting the deficiency in the blood. Maintenance of accurate levels of blood calcium is more important, physiologically, than the strength of the bones. Secretion of abnormal quantities of PTH from a parathyroid tumour can lead to bone softening. Underaction of the parathyroids causes a dangerous drop in the blood calcium.

Sandström,

Ivor V., swedish anatomist, 1852-1889.
Sandström bodies - Synonym(s): parathyroid glands
References in periodicals archive ?
It has been noted that when all four parathyroid glands were preserved per-operatively, only 5 patients (11.9%) developed transient hypocalcaemia, no patients developed permanent hypocalcaemia and 15 patients (35.7%) did not develop any symptoms of hypocalcaemia.
A number of scintigraphic methods were improved for preoperative pinpoint of hyperfunctional parathyroid glands in the past decade.
Number of parathyroid glands or inadvertently excised were not analysed due to small numbers in subgroups.
MIBI scan, CT, MRI, and venous blood sampling), more ectopic parathyroid glands can be detected in patients with hyperparathyroidism symptoms (10).
A parathyroid gland is considered to be enlarged if it measures greater than 5-7 mm long, 1-2 mm thick and 3-4 mm wide.
The parathyroid gland is the overall regulatory organ that maintains calcium homeostasis through their capacity to sense even minute changes in the level of blood calcium.
Caption: Figure 2: Microscopic finding from the parathyroid glands. (a) Right inferior paratiroid hyperplasia (H&E stain).
Speck et al., "Altered parathyroid gland function in severely immunocompromised patients infected with human immunodeficiency virus," The Journal of Clinical Endocrinology & Metabolism, vol.
Myschetzky, "Preoperative localization of hyperfunctioning parathyroid glands with 4D-CT," European Archives of OtoRhino-Laryngology, vol.
Among the etiology of pHPT, the parathyroid adenoma is the most frequent cause (80%) followed by other pathologies such as endocrine disorders of multiple neoplasia (MEN 1 and MEN 2A), hyperplasia of the parathyroid glands, or even carcinoma (1%) [3].
Tisell, "Autotransplantation of diseased parathyroid glands into subcutaneous abdominal adipose tissue," Surgery, vol.

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