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

/par·a·thy·roid/ (-thi´roid)
1. situated beside the thyroid gland.
2. see under 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.

parathyroid

1. situated beside the thyroid gland.
2. one of the parathyroid glands.
3. a preparation containing parathyroid hormone from animal parathyroid glands; used for diagnosis and treatment of hypoparathyroidism.

parathyroid calcium-regulating hormone
see parathyroid hormone (below).
parathyroid cyst
remnants of the embryonic duct that connects the parathyroid and the thymus during embryogenesis. Called also Kursteiner's cyst.
parathyroid gland
small body in the region of the thyroid gland, occurring in a variable number of pairs, commonly two.
The parathyroid contains two types of cell: 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.
parathyroid gland hyperplasia
may be focal and nodular or, more importantly diffuse. The latter occurs in cases suffering long-standing nutritional deficiency of calcium or renal insufficiency.
parathyroid hormone (PTH)
a simple, straight-chain polypeptide, synthesized in chief cells and stored in secretory granules. The hormone stimulates the formation and activity of resorptive osteocytes so that calcium is released into body fluids without extensive bone remodeling. This is its mineral homeostatic function and is a relatively quick, short duration response. It is also concerned in skeletal homeostasis by stimulating osteoclastic osteolysis, the slower acting process of bone remodeling.
parathyroid hormone-related protein, parathyroid hormone-like peptide
associated with humoral hypercalcemia of malignancy (HHM); see pseudohyperparathyroidism.
parathyroid hyperfunction
parathyroid secretory protein
stored in secretory granules with parathyroid hormone but has no known function. Called also chromogranin A.
parathyroid tumors
carcinomas occur rarely and adenomas more commonly, particularly in older dogs. Either type of tumor may be nonfunctional or functional, causing a primary hyperparathyroidism.
References in periodicals archive ?
Upon parathyroid scintigraphy, focal involvement (parathyroid adenoma?
However, the postoperative rate of parathyroid injury (including mistaken incision rate and postoperative temporary hypoparathyroidism) of the nano-carbon group was significantly lower than that of the methylene blue group.
In a second study of 195 indeterminate thyroid nodule FNA samples, the next-generation classifier was highly accurate at distinguishing parathyroid from non-parathyroid tissue (sensitivity and specificity of 100% each).
Parathyroid adenomas, accounting for 75 to 85% of primary hyperparathyroidism, classically present with symptoms of hypercalcemia (nephrolithiasis, abdominal pain, and psychiatric symptoms) and skeletal disease.
Later on, pathological examination identified the masses as parathyroid adenoma (retrosternal mass) and parathyroid cyst (nodule posterior to the right lobe of thyroid).
The bottom row depicts delayed images (2 hours post-injection), demonstrating retention of tracer (red arrow) in the above mentioned focus with "wash-out" from the thyroid gland, which represents a hyper-functioning/ hyper-metabolic parathyroid adenoma.
Long-term functionality of cryopreserved parathyroid autografts: a 13-year prospective analysis.
Sometimes the diagnosis of cancer is difficult even after surgery due to the similarity between parathyroid cancer cells and noncancerous adenoma cells.
An explorative cervicotomy was performed in three patients with resection of the parathyroid adenoma.
Galectin-3 is thought to contribute to the differential diagnosis of benign and malignant parathyroid tumors.
Surgical removal of the parathyroid glands is another cause as is, and more rarely, autoimmune or congenital diseases, according to the FDA.
Chief cells of the parathyroid glands secrete parathyroid hormone (PTH), also known as parathormone or parathyrin.