Endocrine - Thymus Development: Difference between revisions

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Notice - Mark Hill

Currently this page is only a template and will be updated (this notice removed when completed).

Introduction

Embryonic origins of the endocrine organs of the neck

The thymus has two origins for the lymphoid thymocytes and the thymic epithelial cells. The thymic epithelium begins as two flask-shape endodermal diverticula that form from the third pharyngeal pouch and extend lateralward and backward into the surrounding mesoderm and neural crest-derived mesenchyme in front of the ventral aorta. The immune system T cells are essential for responses against infections and much research concerns the postnatal development of T cells within the thymus.

Historic Embryology - Endocrine
1903 Islets of Langerhans \| 1903 Pig Adrenal \| 1904 interstitial Cells \| 1908 Pancreas Different Species \| 1908 Pituitary \| 1908 Pituitary histology \| 1911 Rathke's pouch \| 1912 Suprarenal Bodies \| 1914 Suprarenal Organs \| 1915 Pharynx \| 1916 Thyroid \| 1918 Rabbit Hypophysis \| 1920 Adrenal \| 1935 Mammalian Hypophysis \| 1926 Human Hypophysis \| 1927 Adrenal \| 1927 Hypophyseal fossa \| 1930 Adrenal \| 1932 Pineal Gland and Cysts \| 1935 Hypophysis \| 1935 Pineal \| 1937 Pineal \| 1935 Parathyroid \| 1940 Adrenal \| 1941 Thyroid \| 1950 Thyroid Parathyroid Thymus \| 1957 Adrenal

| Lecture - Head Development | original page

Historic Embryology
1909 Lymph glands \| 1912 Development of the Lymphatic System \| 1918 Gray's Lymphatic Images \| 1916 Pig Lymphatics \| 1919 Chicken Lymphatic \| 1921 Spleen \| 1922 Pig Stomach Lymphatics \| 1932 Cat Pharyngeal Tonsil \| Historic Disclaimer

Some Recent Findings

Decision checkpoints in the thymus^[1]"The development of T cells in the thymus involves several differentiation and proliferation events, during which hematopoietic precursors give rise to T cells ready to respond to antigen stimulation and undergo effector differentiation."

Thymus Development

Developing Human Thymus (stage 22)

Endoderm - third pharyngeal pouch
Week 6 - diverticulum elongates, hollow then solid, ventral cell proliferation
Thymic primordia - surrounded by neural crest mesenchyme, epithelia/mesenchyme interaction

Thymus - bone-marrow lymphocyte precursors become thymocytes, and subsequently mature into T lymphocytes (T cells)
Thymus hormones - thymosins stimulate the development and differentiation of T lymphocytes


B2 Pharyngeal Arch Pouches 3 and 4 (stage 13)	D1 Developing Human Thymus (stage 22)

Thymus Involution

A postnatal process defined as a decrease in the size, weight and activity of the gland with advancing age. In a recent review^[2], thymic involution was described as a result of high levels of circulating sex hormones, in particular during puberty, and a lower population of precursor cells from the bone marrow and finally changes in the thymic microenvironment.

References

↑ <pubmed>20644572</pubmed>
↑ <pubmed>20354268 </pubmed>

Reviews

Articles

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Endocrine Development - All (14277) Review (4620) Free Full Text (3140)

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Additional Images

Adult Histology

Terms

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Cite this page: Hill, M.A. (2024, April 16) Embryology Endocrine - Thymus Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Endocrine_-_Thymus_Development

What Links Here?

[1] <pubmed>20644572</pubmed>

[2] <pubmed>20354268 </pubmed>

[1]

[2]

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 <pubmed>18304000</pubmed>
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 ===Articles===