The
eyes
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conve ...
begin to
develop
Develop or DEVELOP may refer to:
* ''Develop'' (magazine), a trade publication for the video game industry
* ''Develop'' (Apple magazine), a technical magazine formerly published by Apple Computer
* Develop (chess), moving a piece from its origina ...
as a pair of
diverticula
In medicine or biology, a diverticulum is an outpouching of a hollow (or a fluid-filled) structure in the body. Depending upon which layers of the structure are involved, diverticula are described as being either true or false.
In medicine, t ...
(pouches) from the lateral aspects of the
forebrain
In the anatomy of the brain of vertebrates, the forebrain or prosencephalon is the Anatomical terms of location#Directional terms, rostral (forward-most) portion of the brain. The forebrain (prosencephalon), the midbrain (mesencephalon), and hin ...
. These diverticula make their appearance before the closure of the anterior end of the
neural tube
In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural fold become elevated, a ...
; after the closure of the tube around the 4th week of development, they are known as the optic vesicles. Previous studies of optic vesicles suggest that the surrounding extraocular tissues – the surface
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 ...
and extraocular
mesenchyme
Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood or bone. The interactions between mesenchyme and epithelium help to form nearly every o ...
– are necessary for normal eye growth and differentiation.
They project toward the sides of the head, and the peripheral part of each expands to form a hollow bulb, while the proximal part remains narrow and constitutes the
optic stalk
The optic vesicles project toward the sides of the head, and the peripheral part of each expands to form a hollow bulb, while the proximal part remains narrow and constitutes the optic stalk.
Closure of the choroidal fissure in the optic stalk o ...
, which goes on to form the
optic nerve
In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, visual information from the retina to the brain. In humans, the optic nerve i ...
.
Additional images
File:Gray460.png, Head of chick embryo of about thirty-eight hours’ incubation, viewed from the ventral surface. X 26
See also
*
Eye development
Eye formation in the human embryo begins at approximately three weeks into embryonic development and continues through the tenth week.Ort, D., David, H."Development of the Eye" Retrieved 22 April 2015. Cells from both the mesodermal and the ect ...
References
Citations
Sources
* Fuhrmann, S. (2010). Eye Morphogenesis and Patterning of the Optic Vesicle. Current Topics in Developmental Biology Invertebrate and Vertebrate Eye Development, 61–84. doi:10.1016/b978-0-12-385044-7.00003-5
External links
*
Overview at vision.ca
Embryology of nervous system
Human eye
{{eye-stub