Endocrine - Parathyroid Development: Difference between revisions
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[[File:Pharyngeal_pouches.jpg|thumb|Embryonic origins of the endocrine organs of the neck]] | [[File:Pharyngeal_pouches.jpg|thumb|Embryonic origins of the endocrine organs of the neck]] | ||
The parathyroid gland appears in the adult as a pair of inferior and a pair of superior "bumps" on the beside the (dorsal) thyroid (hence the name, "para"). The embryonic origin of this gland is from the third and fourth pharyngeal pouches | The {{parathyroid}} gland appears in the adult as a pair of inferior and a pair of superior "bumps" on the beside the (dorsal) thyroid (hence the name, "para"). The embryonic origin of this gland is from the {{endoderm}} of the third and fourth pharyngeal pouches, and could also have ectoderm and neural crest contributions. This developmental process also generates multiple small parathyroid clusters in addition to the main parathyroid glands.{{#pmid:21203493|PMID21203493}} | ||
At 6 weeks a diverticulum elongates from the pouch, initially hollow and then solidifynig with cell proliferation. | At 6 weeks a diverticulum elongates from the pouch, initially hollow and then solidifynig with cell proliferation. | ||
Interestingly, the inferior parathyroid originates from the third pharyngeal pouch and the superior arises from the fourth pharyngeal pouch, the adult anatomical position is the opposite of the pharyngeal rostro-caudal order. This occurs due to the third pharyngeal pouch also giving rise to the thymus, the superior pair descend along with the thymus. | |||
Parathyroid hormone (PTH) regulates calcium and phosphate levels in conjunction with parafollicular cells of the {{thyroid}} gland (calcitonin) and Vitamin D (dietary or synthesized in the skin). | |||
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==Parathyroid Hormone== | ==Parathyroid Hormone== | ||
(PTH, parathormone or parathyrin) A polypeptide (84 amino acids) hormone which increases the concentration of calcium ions in the blood. Its actions oppose the hormone [[C#calcitonin|calcitonin]] from the | (PTH, parathormone or parathyrin) A polypeptide (84 amino acids) hormone which increases the concentration of calcium ions in the blood. Its actions oppose the hormone [[C#calcitonin|calcitonin]] from the parafollicular cells (C cells) of the thyroid gland, which decrease calcium. Acts through the parathyroid hormone receptor in bone, kidney and gastrointestinal tract. | ||
* stimulate osteoclasts - degrade bone matrix, releasing calcium | * stimulate osteoclasts - degrade bone matrix, releasing calcium |
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Introduction
The parathyroid gland appears in the adult as a pair of inferior and a pair of superior "bumps" on the beside the (dorsal) thyroid (hence the name, "para"). The embryonic origin of this gland is from the endoderm of the third and fourth pharyngeal pouches, and could also have ectoderm and neural crest contributions. This developmental process also generates multiple small parathyroid clusters in addition to the main parathyroid glands.[1]
At 6 weeks a diverticulum elongates from the pouch, initially hollow and then solidifynig with cell proliferation.
Interestingly, the inferior parathyroid originates from the third pharyngeal pouch and the superior arises from the fourth pharyngeal pouch, the adult anatomical position is the opposite of the pharyngeal rostro-caudal order. This occurs due to the third pharyngeal pouch also giving rise to the thymus, the superior pair descend along with the thymus.
Parathyroid hormone (PTH) regulates calcium and phosphate levels in conjunction with parafollicular cells of the thyroid gland (calcitonin) and Vitamin D (dietary or synthesized in the skin).
The fetal parathyroids appear functional as they respond to calcium levels. The fetal calcium levels also higher than maternal levels.
Historically, see also the 1938 paper on the fate of the ultimobranchial body within the human thyroid gland.[2]
Some Recent Findings
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More recent papers |
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More? References | Discussion Page | Journal Searches | 2019 References | 2020 References Search term: Parathyroid Embryology <pubmed limit=5>Parathyroid Embryology</pubmed> |
Development Overview
- Endoderm - third and fourth pharyngeal pouches, could also have ectoderm and neural crest
- 3rd Pharyngeal Pouch - inferior parathyroid, initially descends with thymus
- 4th Pharyngeal Pouch - superior parathyroid
- Week 6 - diverticulum elongate, hollow then solid, dorsal cell proliferation
- Fetal parathyroids - respond to calcium levels, fetal calcium levels higher than maternal
Parathyroid Hormone
(PTH, parathormone or parathyrin) A polypeptide (84 amino acids) hormone which increases the concentration of calcium ions in the blood. Its actions oppose the hormone calcitonin from the parafollicular cells (C cells) of the thyroid gland, which decrease calcium. Acts through the parathyroid hormone receptor in bone, kidney and gastrointestinal tract.
- stimulate osteoclasts - degrade bone matrix, releasing calcium
- increase calcium gastrointestinal tract absorption
(PTHrP) Originally identified in the clinical syndrome humoral hypercalcemia of malignancy. It's developmental role is that of a regulatory protein expressed during the formation of many organs.
- mammary gland development - epithelial-mesenchymal interactions[4]
- chondrocyte differentiation[5]
Abnormalities
Hyperparathyroidism
Postnatal
- Postnatal adult ageing increased parathyroid hormone plasma levels are associated with cognitive decline and dementia.
- Parathyroid carcinoma (cancer) is a rare malignancy, occurring with an incidence of 0.5 to 4% of all cases of primary hyperparathyroidism.
Adult Histology
References
- ↑ 1.0 1.1 1.2 1.3 Liu Z, Farley A, Chen L, Kirby BJ, Kovacs CS, Blackburn CC & Manley NR. (2010). Thymus-associated parathyroid hormone has two cellular origins with distinct endocrine and immunological functions. PLoS Genet. , 6, e1001251. PMID: 21203493 DOI.
- ↑ Kingsbury BF. On the fate of the ultimobranchial body within the human thyroid gland. (1935) Anat. Rec. 61(2): 155–173.
- ↑ Chojnowski JL, Masuda K, Trau HA, Thomas K, Capecchi M & Manley NR. (2014). Multiple roles for HOXA3 in regulating thymus and parathyroid differentiation and morphogenesis in mouse. Development , 141, 3697-708. PMID: 25249461 DOI.
- ↑ Dunbar ME & Wysolmerski JJ. (1999). Parathyroid hormone-related protein: a developmental regulatory molecule necessary for mammary gland development. J Mammary Gland Biol Neoplasia , 4, 21-34. PMID: 10219904
- ↑ Alman BA & Wunder JS. (2008). Parathyroid hormone-related protein regulates glioma-associated oncogene transcriptional activation: lessons learned from bone development and cartilage neoplasia. Ann. N. Y. Acad. Sci. , 1144, 36-41. PMID: 19076361 DOI.
Reviews
Zajac JD & Danks JA. (2008). The development of the parathyroid gland: from fish to human. Curr. Opin. Nephrol. Hypertens. , 17, 353-6. PMID: 18660669 DOI.
Parvari R, Diaz GA & Hershkovitz E. (2007). Parathyroid development and the role of tubulin chaperone E. Horm. Res. , 67, 12-21. PMID: 17008776 DOI.
Jüppner H. (2000). Role of parathyroid hormone-related peptide and Indian hedgehog in skeletal development. Pediatr. Nephrol. , 14, 606-11. PMID: 10912527
Articles
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- Parathyroid Development - All (3523) Review (768) Free Full Text (741)
Search Pubmed: parathyroid development
Additional Images
Terms
- parathyroid hormone - (PTH, parathormone or parathyrin) A polypeptide (84 amino acids) hormone secreted by the parathyroid gland, which increases the concentration of calcium ions in the blood. Its actions oppose the hormone calcitonin from the thyroid gland parafollicular cells (C cells), which decrease calcium. Acts through the parathyroid hormone receptor located mainly in bone, kidney and gastrointestinal tract. Hormone dual role is to: stimulate osteoclasts in bone to degrade bone matrix releasing calcium; increase gastrointestinal tract absorption of calcium.
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Cite this page: Hill, M.A. (2024, June 20) Embryology Endocrine - Parathyroid Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Endocrine_-_Parathyroid_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G