In
embryogenesis
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...
, Rathke's pouch is an evagination at the roof of the developing mouth in front of the
buccopharyngeal membrane
The region where the crescentic masses of the ectoderm and endoderm come into direct contact with each other constitutes a thin membrane, the buccopharyngeal membrane (or oropharyngeal membrane), which forms a septum between the primitive mouth and ...
. It gives rise to the
anterior pituitary
A major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis or pars anterior) is the glandular, anterior lobe that together with the posterior lobe (posterior pituitary, or the neurohypophysis) makes up the p ...
(adenohypophysis), a part of the
endocrine system
The endocrine system is a messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs. In vertebrates, the hypothalamus is the neu ...
.
Development
Rathke's pouch, and therefore the anterior pituitary, is derived from
ectoderm
The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer, and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from t ...
.
The pouch eventually loses its connection with the
pharynx
The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...
giving rise to the
anterior pituitary
A major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis or pars anterior) is the glandular, anterior lobe that together with the posterior lobe (posterior pituitary, or the neurohypophysis) makes up the p ...
. The anterior wall of Rathke's pouch proliferates, filling most of the pouch to form ''
pars distalis'' and ''
pars tuberalis''. The posterior wall forms ''
pars intermedia''.
In some organisms, the proliferating anterior wall does not fully occupy Rathke's pouch, leaving a remnant (Rathke's cleft) between the ''pars distalis'' and ''pars intermedia''.
Clinical significance
Rathke's pouch may develop benign
cysts
A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubble) ...
.
Craniopharyngioma
A craniopharyngioma is a rare type of brain tumor derived from pituitary gland embryonic tissue that occurs most commonly in children, but also affects adults. It may present at any age, even in the prenatal and neonatal periods, but peak incidence ...
is a neoplasm which can arise from the epithelium within the cleft.
Eponym
It is named for
Martin Rathke
Martin Heinrich Rathke (25 August 1793, Danzig – 3 September 1860, Königsberg) was a German embryologist and anatomist. Along with Karl Ernst von Baer and Christian Heinrich Pander, he is recognized as one of the founders of modern embryol ...
.
[M. H. Rathke. Entwicklungsgeschichte der Natter (Coluber natrix). Königsberg, Bornträger, 1839.]
See also
*
Rathke's cleft cyst
References
External links
*
*
Diagram at cushings-help.com* https://web.archive.org/web/20070930075847/http://www.lib.mcg.edu/edu/eshuphysio/program/section5/5ch2/s5ch2_2.htm
{{Development of digestive system
Embryology of digestive system