2017 Group Project 4

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2017 Student Projects 
Student Projects: 1 Cerebral Cortex | 2 Kidney | 3 Heart | 4 Eye | 5 Lung | 6 Cerebellum
Student Page - here is the sample page I demonstrated with in the first labs.I remind all students that you have your own Group Forum on Moodle for your discussions, it is only accessible by members of your group.
Editing Links: Editing Basics | Images | Tables | Referencing | Journal Searches | Copyright | Font Colours | Virtual Slide Permalink | My Preferences | One Page Wiki Card | Printing | Movies | Language Translation | Student Movies | Using OpenOffice | Internet Browsers | Moodle | Navigation/Contribution | Term Link | Short URLs | 2018 Test Student

Eye Development

Introduction to the eye

The eye is a complex structure which allows a variety of species to intake and process visual information from the world around us.

In humans the wall of the eye has 3 basic layers: - An outer fibrous layer containing the posterior sclera and anterior cornea. The sclera --- - A vascular middle layer containing the choroid - An inner receptive layer containing the retina

Anterior structure

ref: https://ap01-a.alma.exlibrisgroup.com/view/uresolver/61UNSW_INST/openurl?ctx_enc=info:ofi/enc:UTF-8&ctx_id=10_1&ctx_tim=2017-09-07T14%3A11%3A09IST&ctx_ver=Z39.88-2004&url_ctx_fmt=info:ofi/fmt:kev:mtx:ctx&url_ver=Z39.88-2004&rfr_id=info:sid/primo.exlibrisgroup.com-scopus&req_id=&rft_val_fmt=info:ofi/fmt:kev:mtx:book&rft.genre=bookitem&rft.atitle=Anatomy%20of%20the%20eye&rft.jtitle=&rft.btitle=Handbook%20of%20Visual%20Display%20Technology&rft.aulast=Garhart&rft.auinit=C&rft.auinit1=&rft.auinitm=&rft.ausuffix=&rft.au=Garhart,%20C.&rft.aucorp=&rft.date=20120101&rft.volume=1&rft.issue=&rft.part=&rft.quarter=&rft.ssn=&rft.spage=73&rft.epage=82&rft.pages=73-82&rft.artnum=&rft.issn=&rft.eissn=&rft.isbn=9783540795674&rft.sici=&rft.coden=&rft_id=info:doi/10.1007/978-3-540-79567-4_2.1.1&rft.object_id=&rft.eisbn=&rft.edition=&rft.pub=Springer%20Berlin%20Heidelberg&rft.place=&rft.series=&rft.stitle=&rft.bici=&rft_id=info:bibcode/&rft_id=info:hdl/&rft_id=info:lccn/&rft_id=info:oclcnum/&rft_id=info:pmid/&rft_id=info:eric/((addata/eric}}&rft_dat=%3Cscopus%3E2-s2.0-84923867273%3C/scopus%3E,language=eng,view=UNSWS&svc_dat=single_service&env_type=test

Timeline of Eye Development

Development of the eye components

The eyes are derived from four sources:

  • The neuroectoderm of the forebrain forms
    • Retina
    • Posterior layers of the iris
    • The optic nerve.
  • The surface ectoderm of the head forms
    • The lens of the eye
    • The corneal epithelium.
  • The mesoderm between the neuroectoderm and the surface ectoderm forms
    • The fibrous and vascular coats of the eye
  • The neural crest cells forms
    • Choroid
    • Sclera
    • Corneal endothelium


INSERT PICTURE The eye starts to develop at 22 days. The optic grooves (sulci) appears in the neural folds at the cranial end of the embryo. When the neural fold fuse to form the forebrain, the optic grooves will form optic vesicles. The optic vesicles are continuous cavities from the cavity of the forebrain and project from the wall of the forebrain and into the mesenchyme. The optic vesicle extends from the diencephalon and will come in contact with the surface ectoderm of the head. This induces the formation of a lens placode. The surface ectoderm near the optic vesicles will thicken and form the lens placodes. The lens placodes will sink into the surface ectoderm and form lens pits. The edges of the lens pits will travel towards each other and fuse to form round lens vesicles, which will later lose connection with the surface ectoderm. The optic vesicles do also keep developing - they will form double-walled optic cups which are connected to the brain by the optic stalk. The two layers of the optic cup will differentiate in different directions. The cells of the outer layer will produce melanin pigment and later become the pigmented retina. The cells of the inner layer of the optic cup will proliferate fast and develop glia, ganglion cells, interneurons and light-sensitive photoreceptor neurons. These cells are in the neural retina. The ganglion cells of the retina are neurons that send signal to the brain. The retinal ganglion cells' axons will meet at the base of the eye and go down the optic stalk. The optic stalk is now the optic nerve [1]

The optic cups will fold inwards around the lens while the lens vesicles have grown inwards so they have fully lost their connection with the surface ectoderm, which locates them in the cavities of the optic cups. The retinal fissures (linear grooves) will develop and cover the ventral surface of the optic cups and down to the optic stalk. The retinal fissures contain vascular mesenchyme and hyaloid blood vessels will develop here. The hyaloid artery supplies the structures in the eye with blood and the hyaloid vein will return the blood from these structures.

"Formation of the optic vesicle"

It is a specific area of the neural ectoderm that will become the optic vesicle - this happens because of a group of transcription factors - Six3, Pax6, and Rx1. These transcription factors are expressed in the most anterior tip of the neural plate. This area will split into bilateral regions and form the optic vesicles. The Pax6 protein has shown to be especially important for the development of the lens and retina. This protein is important for photoreceptive cells in all phyla. Pax 6 is also present in the murine forebrain, hindbrain, and nasal placodes, but the eyes are most sensitive its absence [2].

The sonic hedgehog gene is important for the separation of the single eye field into two fields. If this gene is inhibited, the eye field will not split which will result in cyclopia, a single eye in the center of the face [3].



Retina

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Optic Nerve

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The axons of the ganglion cells of the neural retina will grow in the wall of the optic nerve. The cavity in the optic nerve will start disappearing, and instead, the axons of the ganglion cells will form the optic nerve.


Ciliary Body

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http://www.sciencedirect.com/science/article/pii/S0012160606014898?via%3Dihub

Iris

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Lens

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Lens cells comes from ectoderm and differentiate into either lens fibers or the lens epithelium. The lens fibers create the lens mass and the lens epithelium makes the sheet of cuboida epithelium covering the anterious surface of the lens [4]

http://dev.biologists.org/content/141/23/4432.long

http://www.sciencedirect.com/science/article/pii/S0014483510000448

Aquous Chambers

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Cornea

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http://www.sciencedirect.com/science/article/pii/S1877117315000642

Choroid and Sclera

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[5]

Eyelids

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Lacrimal Glands

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Extraocular muscles

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<pubmed>26410132</pubmed> <pubmed>23071378</pubmed>

Common Abnormalities

We could talk briefly in this sections about the causes of short/long-sightedness and common causes of blindness at a developmental level - z3416557

Further Research

5117343 In the news, media, websites starting point: Macular Research: https://www.cera.org.au/research/macular-research/ > Bionic Eye - https://theconversation.com/artificial-vision-what-people-with-bionic-eyes-see-79758 Corneal Research: https://www.cera.org.au/research/corneal-research/ > Stem cells, corneal transplant Cellular Reprogramming: https://www.cera.org.au/cellular-reprogramming/ Glaucoma Research: https://www.cera.org.au/research/glaucoma-research/

Glossary

References

Recent papers

Mark Hill (talk) 10:15, 14 August 2017 (AEST) OK Group 4 below are some starting places.

<pubmed limit=5>Eye+Development</pubmed>

z5075309 - <pubmed>26956898</pubmed>

External links

Vision Links: vision | lens | retina | placode | extraocular muscle | cornea | eyelid | lacrima gland | vision abnormalities | Student project 1 | Student project 2 | Category:Vision | sensory
Historic Embryology - Vision 
Historic Embryology: 1906 Eye Embryology | 1907 Development Atlas | 1912 Eye Development | 1912 Nasolacrimal Duct | 1917 Extraocular Muscle | 1918 Grays Anatomy | 1921 Eye Development | 1922 Optic Primordia | 1925 Eyeball and optic nerve | 1925 Iris | 1927 Oculomotor | 1928 Human Retina | 1928 Retina | 1928 Hyaloid Canal | Historic Disclaimer

PubMed Searches: Eye Development | Vision Development

BMC Dev Biol Search: Eye Development