development of eye and ear (special embryology)
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DEVELOPMENT OF THE EYE
(Page 185)
Dr.Sherif Fahmy
Anatomy of The Eye
Dr.Sherif Fahmy
Ciliary body
Iris CorneaLens
Sclera
Choroid
Retina
Anterior Chamber
Vitreous humour
Optic nerve
Posterior chamber
Coats: outer, middle and inner.
Dr.Sherif Fahmy
Development of the eye• -Starts at the beginning of the 4th week.• -Bilateral diverticulum from forebrain at level of
diencephalon.• -This diverticulum forms optic vesicle and optic
stalk.• -Optic vesicle will be optic cup which form retina,
iris and ciliary body. The mouth of the cup will form pupil.
• Inner layer of the cup forms nervous layer of retina while the outer layer forms the pigmented layer of retina.
• Optic stalk forms optic nerve and invaginated by hyaloid artery which will be central retinal artery.
Dr.Sherif Fahmy
-Lens placode is formed from thickened surface ectoderm. It becomes invaginated to form lens vesicle. At 5th week, lens vesicle loss contact with surface ectoderm and enters through the mouth of optic vesicle.-Cornea is developed from surface ectoderm and underlying mesoderm.-Sclera and choroid are developed from mesoderm around optic cup.-Vitreous body is developed from mesoderm that fill optic cup.-Eyelids are developed from ectoderm and mesoderm that covers the cornea.
Dr.Sherif Fahmy
Lacrimal Apparatus• Lacrimal gland: Formed from a group of
ectodermal buds that are formed in the upper lateral angle of conjunctival sac. The buds fuse together and become canalised.
• Lacrimal sac & nasolacrimal ducts: are formed from cord of ectodermal cells between frontonasal process and maxillary process.
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Congenital anomalies of the eye• 1- anophthalmia. Absence of the eye.• 2- Microphthalmia: small eye.• 3- Cyclopia: single eye.• 4- Congenital cataract: whitening of the
lens.• 5- Congenital aphakia: absence of the
lens.• 6- Coloboma iridis: cleft iris.
Dr.Sherif Fahmy
THE EAR• External & middle ears see
pharyngeal apparatus.• Internal ear is formed by
formation of otic vesicle from surface ectoderm.
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Dr.Sherif Fahmy
Dr.Sherif Fahmy