Eye vesicles

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As optic vesicle or vesicle optica is called the paired lateral protuberance the wall of the embryonic front brain bubble ( forebrain ) in the region of the later diencephalon ( diencephalon ).

Drawing of a cross section in height of the embryonic forebrain -
optic vesicle ( "optic vesicle") when changing to the eye cup ( "optic cup") during the constriction of the lens placode the lens vesicle.

Go out of the optic vesicle after invagination to doppelblättrigen eye cup ( cupula optica the layers of) the retina ( retinal ) together with the pigment epithelium ( stratum pigmentosum of) the eye out while the optic vesicle stem ( peduncle opticus ) becomes the eye cup stem through which then the optic nerve ( nervus opticus ) from the retina to the diencephalon. The transformation to the eye cup begins after the formation of the lens placode , a thickening in the surface ectoderm as an attachment to the eye lens, which is induced by the underlying ocular vesicle .

Even before the lens vesicle constricts from the ectoderm, the wall of the neuroectodermal vesicle sinks into a double-walled eye cup. The deepening cleft of the eye cup arises between the folds of the eye and extends medially into the stem of the eye cup and, in addition to vessels, also receives the nerve fibers from the retina. Then the gap is closed from the back of the eye cup by the fold edges merging (an incomplete closure leads to colobomas ). At the front edge of the cup, however, there remains an opening - here the edge of the envelope later becomes the rear surface of the iris and forms the pupil over the deeper sunken lens. While the layers of the inner eyeball (retina pigment epithelium) from the inner and outer sheet of the optic cup arise and come from so neuroectoderm arise surrounding portions of the middle and sclera - choroid (choroidal), sclera (dermis) and the cornea (cornea) - from the mesenchyme of the head area.

See also

Individual evidence

  1. Klaus V. Hinrichsen (Ed.): Humanembryology: Textbook and atlas of the prenatal development of humans. Springer, Berlin 2013, ISBN 978-3-662-07816-7 ; Chapter 18: Eye Development, p. 477ff.
  2. ^ Norbert Ulfig: short textbook embryology. 2nd edition. Thieme, Stuttgart 2009, ISBN 978-3-131-52702-8 ; Chapter 10.1.2: The eye vesicle , the lens placode and the eye cup , p. 145f.
  3. Werner A. Müller, Monika Hassel: Developmental and reproductive biology of humans and animals. An introductory textbook. 4th edition. Springer, Berlin et al. 2006, ISBN 3-540-24057-8 ; Chapter 12.4.3: The induction of the eye lens is a textbook example of a downstream induction process , p. 257.