parathyroid

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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.

par·a·thy·roid

(par'ă-thī'royd),
1. Adjacent to the thyroid gland.
2. Synonym(s): parathyroid gland

parathyroid

(păr′ə-thī′roid)
adj.
1. Of, relating to, or obtained from the parathyroid glands: a parathyroid extract.
2. Adjacent to the thyroid gland.
n.
1. Any of the parathyroid glands.
2. A parathyroid hormone.

parathyroid

adjective Referring to the parathyroid gland.

noun Parathyroid gland (see there); glandulae parathyroideae [NA6].

par·a·thy·roid

(par'ă-thī'royd)
1. Adjacent to the thyroid gland.
2. Synonym(s): parathyroid gland.

parathyroid

an endocrine gland of higher vertebrates that is situated in or near the thyroid gland and controls the calcium level of the blood. When too little [Ca+] is present in the blood, parathormone is secreted which:
  1. (a) reduces the OSTEOBLAST activity and thus the amount of bone-matrix formation,
  2. (b) increases [Ca+] uptake from the gut into the blood stream, and
  3. (c) acts on the kidney tubules, decreasing calcium and phosphate excretion. Undersecretion of parathormone results in a fall of blood calcium and causes TETANY.
References in periodicals archive ?
Ectopic parathyroid adenoma was suspected, and a mediastinal mass was identified in a chest computer tomography (CT) scan.
Exclusion criteria include patients over 75 years of age, patients with severe comorbidity with contraindicated surgery or ASA risk score over 3, primary or tertiary hyperparathyroidism, parathyroid carcinoma, parathyromatosis, and mediastinal parathyroid gland localization.
In surgical manipulation during thyroidectomy, inadvertent resection or injury of vascular pedicle of the parathyroid glands can occur, with sudden and significant reduction in the levels of parathyroid hormone, which would lead to parathormone-dependent hypocalcemia [1], which probably causes the transitory hypoparathyroidism.
Thyroid ultrasonography revealed a hypoechoic right infero-posterior nodule of 0.6/0.6/0.5 cm, suggestive for parathyroid adenoma (Figure 1).
A retrospective review of histopathology findings of the thyroid and parathyroid glands at autopsy was conducted at a tertiary care teaching hospital during the year 1980 through 2007.
Conclusion: Autotransplantation of at least one parathyroid gland after total thyroidectomy is a procedure with predictable outcome associated with minimal risk of permanent hypoparathyroidism.
In 1903 Max Askanazy, a pathologist in Geneva, discovered a parathyroid tumour at the post mortem of a patient with this disease, (also called Von Recklinghausen's disease of bone), but, interestingly enough, he made no association between the two.
Microscopically, the mass was an encapsulated nodule that contained both thymic and parathyroid tissue, which appeared as well-demarcated entities within the same capsule (figure, A).
In 1990, the National Institutes of Health set guidelines for surgery in patients with this parathyroid condition.
In FMEN1, all four parathyroid glands tend to be overactive.
As adenoma in the etiology is even more uncommon, only 19 cases have been reported since 1994, and of those cases, adenoma was in both parathyroid glands in only one case (1, 2, 4-20).
Pre-operative serum calcium, Vitamin D (25-hydroxy Vitamin D3) level & intact parathyroid hormone level (iPTH) were obtained in all the cases in addition to general anaesthesia fitness & establishment of euthyroid status.