Endocrine - Parathyroid Development: Difference between revisions
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==Introduction== | ==Introduction== | ||
[[File: | [[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 endoderm, and could also have ectoderm and neural crest contributions. | 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 endoderm, and could also have ectoderm and neural crest contributions. | ||
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* secreted by chief cells | * secreted by chief cells | ||
Principal cells cords of cells | Principal cells cords of cells | ||
==Development Overview== | ==Development Overview== | ||
[[File:Pharyngeal pouches.jpg|thumb|Pharyngeal pouches]] | [[File:Pharyngeal pouches.jpg|thumb|Pharyngeal pouches]] |
Revision as of 14:18, 23 July 2010
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 third and fourth pharyngeal pouches endoderm, and could also have ectoderm and neural crest contributions.
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.
The fetal parathyroids appear functional as they respond to calcium levels. The fetal calcium levels also higher than maternal levels.
| Lecture - Head Development | original page
- Parathyroid Hormone - Increase calcium ions [Ca2+], stimulates osteoclasts, increase Ca GIT absorption (opposite effect to calcitonin)
- Adult Calcium and Phosphate - Daily turnover in human with dietary intake of 1000 mg/day
- secreted by chief cells
Principal cells cords of cells
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 thyroid gland parafollicular cells (C cells), 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[1]
- chondrocyte differentiation[2]
References
- ↑ Parathyroid hormone-related protein: a developmental regulatory molecule necessary for mammary gland development. Dunbar ME, Wysolmerski JJ. J Mammary Gland Biol Neoplasia. 1999 Jan;4(1):21-34. Review. PMID: 10219904
- ↑ Parathyroid hormone-related protein regulates glioma-associated oncogene transcriptional activation: lessons learned from bone development and cartilage neoplasia. Alman BA, Wunder JS. Ann N Y Acad Sci. 2008 Nov;1144:36-41. Review. PMID: 19076361
Reviews
- The development of the parathyroid gland: from fish to human. Zajac JD, Danks JA. Curr Opin Nephrol Hypertens. 2008 Jul;17(4):353-6. Review. PMID: 18660669
- Parathyroid development and the role of tubulin chaperone E. Parvari R, Diaz GA, Hershkovitz E. Horm Res. 2007;67(1):12-21. Epub 2006 Sep 27. Review. PMID: 17008776
- Role of parathyroid hormone-related peptide and Indian hedgehog in skeletal development. Jüppner H. Pediatr Nephrol. 2000 Jul;14(7):606-11. Review. PMID: 10912527
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Cite this page: Hill, M.A. (2024, April 26) 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