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1 The eyes begin to develop from a population of cells in the anterior neural plate at the end of the 4 th week of development. These cells make up the.

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Presentation on theme: "1 The eyes begin to develop from a population of cells in the anterior neural plate at the end of the 4 th week of development. These cells make up the."— Presentation transcript:

1 1 The eyes begin to develop from a population of cells in the anterior neural plate at the end of the 4 th week of development. These cells make up the eye fields.

2 2 Optic grooves (sulci) form as some of the cells in the eye fields invaginates. Optic grooves (sulci) form as some of the cells in the eye fields invaginates. The optic grooves form the optic stalks and the optic vesicles. The optic grooves form the optic stalks and the optic vesicles. Contact between the neural ectoderm of the optic vesicle and the surface ectoderm results in induction of the lens placode. Contact between the neural ectoderm of the optic vesicle and the surface ectoderm results in induction of the lens placode.

3 3 The invaginating lens placode forms the lens vesicle that pinches off the surface ectoderm. Invagination of the optic vesicle forms the bilayered optic cup that remains connected to the forebrain via the optic stalk. The invaginating lens placode forms the lens vesicle that pinches off the surface ectoderm. Invagination of the optic vesicle forms the bilayered optic cup that remains connected to the forebrain via the optic stalk.

4 4 Contact between the surface ectoderm and the budding optic vesicle induces the differentiation of a population of cells that will form the lens placode. Contact between the surface ectoderm and the budding optic vesicle induces the differentiation of a population of cells that will form the lens placode.

5 5 The lens placode invaginates, forming the lens vesicle. Concurrently, the optic vesicle becomes the optic cup. The lens placode invaginates, forming the lens vesicle. Concurrently, the optic vesicle becomes the optic cup. The lens vesicle eventually becomes the lens and the two layers of the optic cup become the neural and pigmented layers of the retina. The lens vesicle eventually becomes the lens and the two layers of the optic cup become the neural and pigmented layers of the retina.

6 6 The optic vesicle and the optic stalk invaginates, forming the choroid fissure inferiorly. The optic vesicle and the optic stalk invaginates, forming the choroid fissure inferiorly.

7 7 The hyaloid artery courses through the choroid fissure. The hyaloid artery courses through the choroid fissure.

8 8 The hyaloid vasculature surrounds the back of the lens. Following separation of the lens from the surface, the posterior lens fibers elongate to obliterate the lens cavity and the cornea begins to differentiate. The hyaloid vasculature surrounds the back of the lens. Following separation of the lens from the surface, the posterior lens fibers elongate to obliterate the lens cavity and the cornea begins to differentiate.

9 9 The anterior chamber of the eye forms as a space develops between the lens and its closely associated iridopupillary membrane and the cornea. The anterior chamber of the eye forms as a space develops between the lens and its closely associated iridopupillary membrane and the cornea.

10 10 The cornea consists of an outer epithelial layer derived from surface ectoderm and inner layers derived from neural crest cells. The cornea consists of an outer epithelial layer derived from surface ectoderm and inner layers derived from neural crest cells. As the retina develops, the pigmented layer becomes relatively thinner while the neural portion thickens. As the retina develops, the pigmented layer becomes relatively thinner while the neural portion thickens.

11 11 As the neural portion develops, it differentiates into distinct cell layers. As the neural portion develops, it differentiates into distinct cell layers.

12 12 The iris forms from the outer rim of the optic cup. The iris forms from the outer rim of the optic cup. At the rim of the optic cup, the inner and outer layers become closely associated. At the rim of the optic cup, the inner and outer layers become closely associated.

13 13 Folding of these layers results in formation of the ciliary processes. Folding of these layers results in formation of the ciliary processes.

14 14 By the end of the embryonic period, eyelids begin to form. By the end of the embryonic period, eyelids begin to form. The eyelids fuse at the beginning of the second trimester and reopen at the beginning of the third trimester. The eyelids fuse at the beginning of the second trimester and reopen at the beginning of the third trimester.

15 15 CONGENITAL MALFORMATIONS Coloboma iridis - failure of closure of choroid fissure due to which cleft persists. Coloboma iridis - failure of closure of choroid fissure due to which cleft persists. Congenital cataract - lens becomes opaque during intrauterine life. Congenital cataract - lens becomes opaque during intrauterine life. Microophthalmia – overall size of the eye is too small. Microophthalmia – overall size of the eye is too small.

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19 19 Embryonic eye, with lens vesicle

20 20 Embryo, brain with optic and lens vesicles


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