GLANDULA PARATIROIDES PDF
Hipercalcemia refractaria secundaria a un carcinoma de paratiroides: respuesta a altas dosis de Denosumab. Las glándulas paratiroideas están justo por detrás de la glándula tiroidea en el cuello. Estas glándulas le ayudan al cuerpo a controlar el nivel. TERMIUM® is the Government of Canada’s terminology and linguistic data bank.
|Published (Last):||4 April 2017|
|PDF File Size:||19.39 Mb|
|ePub File Size:||9.81 Mb|
|Price:||Free* [*Free Regsitration Required]|
Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods that produce parathyroid hormone. Humans usually have four parathyroid glands, variably located on the back of the thyroid gland. Parathyroid hormone and calcitonin one of the hormones made by the thyroid gland have key roles in regulating the amount of calcium in the blood and within the bones.
Parathyroid glands share a similar blood supply, venous drainage, and lymphatic drainage to the thyroid glands. Parathyroid glands are derived from the gllandula lining of the third and fourth pharyngeal poucheswith the superior glands arising from the fourth pouch, and the inferior glands arising from the higher third pouch. The relative position of the inferior and superior glands, which are named according to their final location, changes because of the migration of embryological tissues.
Hyperparathyroidism and hypoparathyroidismcharacterized by alterations in the blood calcium levels and bone metabolismare states of either surplus parairoides deficient parathyroid function.
The parathyroid glands are two pairs of glands usually positioned behind the left and right lobes of the thyroid. The two parathyroid glands on each side which are positioned higher are called the superior parathyroid glands, while the lower two are called the inferior parathyroid glands. Each parathyroid vein drains into the superior, middle and inferior thyroid veins. The superior and middle thyroid veins drain into the internal jugular veinand the inferior thyroid vein drains into the brachiocephalic vein.
Lymphatic vessels from the parathyroid glands pparatiroides into deep cervical lymph nodes and paratracheal lymph nodes. The parathyroid glands are variable in number: The parathyroid glands are named for their proximity to the thyroid — and serve a completely different role than the thyroid gland.
The parathyroid glands are quite easily recognizable from the thyroid as they have densely packed cells, in contrast with the follicular structure of the thyroid. The white round structures are fat cells. The small, dark cells are chief cellswhich are responsible for secreting parathyroid hormone.
In the early development of the human embryoa series of five pharyngeal arches and four pharyngeal pouches form that give rise to the face, neck, and surrounding structures. The pouches are numbered such that the first pouch is the closest to the top of the embryo’s head and the fourth is the furthest from it.
The parathyroid glands originate from the interaction of the endoderm of the third and fourth pouch and neural crest mesenchyme. The pair of glands which is glaandula inferior develops from the third pouch with the thymuswhereas the pair of glands which is ultimately superior develops from the fourth pouch.
During embryological development, the thymus migrates downwards, dragging the inferior glands with it. The superior pair are not dragged downwards by the fourth pouch to the same degree. The glands are named after their final, not embryological, positions. Parathyroid development is regulated by a number of genesincluding those coding for several transcription factors.
The major function of the parathyroid glands is to maintain the body’s calcium and phosphate levels within a very narrow range, so that the nervous and muscular systems can function properly. The parathyroid glands do this by secreting parathyroid hormone PTH. Paratoroides hormone also known as parathormone is a small protein that takes part in the control of calcium and phosphate homeostasisas well as bone physiology.
Parathyroid hormone has effects antagonistic to those of calcitonin. Parathyroid disease is conventionally divided into states where the parathyroid is overactive hyperparathyroidismand states where the parathyroid is under- or hypoactive hypoparathyroidism. Both states are characterised by their symptoms, which relate to the excess or deficiency of parathyroid hormone in the blood.
Hyperparathyroidism is the state in which there is excess parathyroid hormone circulating. This may cause bone pain and tenderness, due to increased bone resorption. Due to increased circulating calcium, there may be other symptoms associated with hypercalcemiamost commonly dehydration. Hyperparathyroidism is most commonly caused by a benign proliferation of chief cells in single gland, and paratiroudes MEN syndrome.
This is known as primary hyperparathyroidism which is generally managed by surgical removal of the abnormal parathyroid gland. Renal disease may lead to hyperparathyroidism. When too much calcium glandjla lost, there is a compensation by the parathyroid, and parathyroid hormone is released.
The glands hypertrophy to synthesise more parathyroid hormone. This is known as secondary hyperparathyroidism. If paratroides situation exists for a prolonged period of time, the parathyroid tissue may become unresponsive to the blood calcium levels, and begin to autonomously release parathyroid hormone.
Parathyroid gland – Wikipedia
This is known as tertiary hyperparathyroidism. The state of decreased parathyroid activity is known as hypoparathyroidism. This is most gandula associated with damage to the glands or their blood supply during thyroid surgery — it may be associated with rarer genetic syndromes such as DiGeorge syndromewhich is inherited as an autosomal dominant syndrome.
Hypoparathyroidism will occur after surgical removal of the parathyroid glands. Occasionally, an individual’s tissues are resistant to the effects of parathyroid hormone. This is known as pseudohypoparathyroidism. In this case the parathyroid glands are fully functional, and the hormone itself is not able to function, resulting in a decrease in blood calcium levels. Pseudohypoparathyroidism is often associated with the genetic condition Albright’s hereditary osteodystrophy.
Pseudo pseudohypoparathyroidism, one of the longest words in the English languageis used to describe an individual with Albright’s psratiroides osteodystrophy; with normal parathyroid hormone and serum calcium levels. Hypoparathyroidism may present with symptoms associated with decreased calciumand is generally treated with Vitamin D analogues.
The parathyroid glands were first discovered in the Indian Rhinoceros by Richard Owen in Physiologist Eugene Gley first documented the putative function of the glands innoting the connection between their removal and the development of muscular tetany.
MacCallum ininvestigating tumours of the parathyroid, proposed their role in calcium metabolism. The paratiroidess successful removal of the parathyroid may have been paratirodes out in by medical doctor Isaac Y Olch, whose intern had noticed elevated calcium levels in an elderly patient with muscle weakness.
Prior to this surgery, patients with removed parathyroid glands typically died from muscular tetany.
Parathyroid hormone was isolated in by Adolph M. Hanson and by James B. Studies of parathyroid hormone levels by Roger GuilleminAndrew Schally and Rosalyn Sussman Yalow led to the development of immunoassays capable of measuring body substances and glabdula Nobel Prize in Parathyroid paratirodes are found in all adult tetrapods ; they vary in their number and position.
Mammals typically have four parathyroid glands, while other types of animals typically have six. The removal of parathyroid glands in animals produces a condition resembling acute poisoning with irregular muscle contractions. Fish do not possess parathyroid glands; several species have been found to express parathyroid hormone.
GLANDULA PARATIROIDES PDF
Developmental genes and calcium-sensing receptors in fish gills are similar to those within the parathyroid glands of birds and mammals. It has been suggested that the tetrapod glands may have been evolutionarily derived from these fish gills.
Scheme showing development of branchial epithelial bodies. From Wikipedia, the free encyclopedia. Parathyroid glands Diagram showing structures in the human neck.
The four green shaded areas represent the most common position of the parathyroid glands, which are generally four in number and situated behind the lateral lobes of the thyroid gland shaded orange. This article uses anatomical terminology; for an overview, see anatomical terminology.
Williams, Peter L; Warwick, Roger, eds. Gray’s Anatomy 36th ed.
Paratiroide – Wikipedia, a enciclopedia libre
Examination of parathyroid gland specimens”. Journal of Clinical Pathology. Mitchell; illustrations by Richard; Richardson, Paul Gray’s anatomy for students. Human embryology 3rd ed. Current Opinion in Nephrology and Hypertension.
Textbook of medical physiology 11th ed. Davidson’s principles and practice of medicine 21st ed.
Science, Medicine and History. American Journal of Kidney Diseases. Journal of the American Medical Association. The history of parathyroid surgery”. Contributions from two continents”. The American Journal of Surgical Pathology. The Journal of Oaratiroides Medicine. Disease and Its Causes. Proceedings of the National Academy of Sciences.
Anatomy of the gkandula system. Pars intermedia Pars tuberalis Pars distalis Acidophil cell Somatotropic cell Prolactin cell Somatomammotrophic cell Basophil cell Corticotropic cell Gonadotropic cell Thyrotropic cell Chromophobe cell.
Pars nervosa Median eminence Stalk Pituicyte Herring bodies. Follicular cell Parafollicular cell. Chief cell Oxyphil cell. Zona glomerulosa Zona fasciculata Zona reticularis. Enteroendocrine cell Paraganglia Organ of Zuckerkandl Placenta Development List of human endocrine organs and actions. Retrieved from ” https: Wikipedia articles needing page number citations from May CS1: Views Read Edit View history.