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Eye Embryology Made Simply Ridiculous

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1 Eye embryology made simply ridiculous Regarding the embryology of the lens: There are two anatomic structures we must concern ourselves with… 2 Eye embryology made simply ridiculous (Outside of embryo; space filled with amniotic fluid) (Cell apices) Surfacesame twoEctoderm words cells resting on the outer body wall of the embryo (Inside of embryo; space filled with embryo stuff) This is the outer body wall of the embryo in the region destined to become the head. The surface of the outer body wall is lined with surfacetwo ectodermwords cells. 3 Eye embryology made simply ridiculous (Outside of embryo; space filled with amniotic fluid) (Cell apices) Surface Ectoderm cells resting on the outer body wall of the embryo (Inside of embryo; space filled with embryo stuff) This is the outer body wall of the embryo in the region destined to become the head. The surface of the outer body wall is lined with surface ectoderm cells. 4 Eye embryology made simply ridiculous This is the optic vesicle, an outpouching of the neural tube. The inner surface of the optic vesicle is lined with neuroectodermone word cells. (Cell apices) Neuroectodermsame one word cells resting on the inner wall of the optic vesicle This way to the neural tube 5 Eye embryology made simply ridiculous This is the optic vesicle, an outpouching of the neural tube. The inner surface of the optic vesicle is lined with neuroectoderm cells. (Cell apices) Neuroectoderm cells resting on the inner wall of the optic vesicle This way to the neural tube 6 Eye embryology made simply ridiculous (Outside of embryo) (Outside of embryo) (Outside of embryo) (Inside of embryo) (Inside of embryo) (Inside of embryo) This is how the surface ectoderm and optic vesicle are spatially related early in embryogenesis. Neuroectoderm cells resting on the inner wall of the optic vesicle This way to the neural tube 7 Eye embryology made simply ridiculous Lenstwo placode words The proximity of the optic vesicle to the surface ectoderm induces those cells to grow taller, forming a structure known as the lenssame placode two words . 8 Eye embryology made simply ridiculous Lens placode The proximity of the optic vesicle to the surface ectoderm induces those cells to grow taller, forming a structure known as the lens placode. 9 Eye embryology made simply ridiculous Lens placode The proximity of the optic vesicle to the surface ectoderm induces those cells to grow taller, forming a structure known as the lens placode. This occurs in the firstunit ofmonth time of embryogenesis. 10 Eye embryology made simply ridiculous Lens placode The proximity of the optic vesicle to the surface ectoderm induces those cells to grow taller, forming a structure known as the lens placode. This occurs in the first month of embryogenesis. 11 Eye embryology made simply ridiculous The optic vesicle starts to invaginate, and… 12 Eye embryology made simply ridiculous The optic vesicle starts to invaginate, and… as it does, the lens placode follows. 13 Eye embryology made simply ridiculous This process of invagination/following continues… 14 Eye embryology made simply ridiculous This process of invagination/following continues… and continues… 15 Eye embryology made simply ridiculous This process of invagination/following continues… and continues… until the two walls of neuroectoderm are apposing, and the surface ectoderm has formed a sphere. 16 Eye embryology made simply ridiculous Note that the surface ectoderm re-establishes a continuous body wall This process of invagination/following continues… and continues… until the two walls of neuroectoderm are apposing, and the surface ectoderm has formed a sphere. 17 Eye embryology made simply ridiculous Note that the surface ectoderm re-establishes a continuous body wall This process of invagination/following continues… and continues… until the two walls of neuroectoderm are apposing, and the surface ectoderm has formed a sphere. Note that this part will become the optictwo wordsnerve 18 Eye embryology made simply ridiculous Note that the surface ectoderm re-establishes a continuous body wall This process of invagination/following continues… and continues… until the two walls of neuroectoderm are apposing, and the surface ectoderm has formed a sphere. Note that this part will become the optic nerve 19 Eye embryology made simply ridiculous Note that the surface ectoderm re-establishes a continuous body wall The re-established surface ectoderm will eventually give rise to a number of eye-related structures: This process of 1) Epithelium of the conjunctiva invagination/following2) Epithelium of the cornea continues… 3) Eyelids and continues… 4) Lacrimal gland until the two walls of neuroectoderm are apposing, and the surface ectoderm has formed a sphere. Note that this part will become the optic nerve 20 Eye embryology made simply ridiculous Note that the surface ectoderm re-establishes a continuous body wall The re-established surface ectoderm will eventually give rise to a number of eye-related structures: This process of 1) Epithelium of the conjunctiva invagination/following2) Epithelium of the cornea continues… 3) Eyelids and continues… 4) Lacrimal gland until the two walls of neuroectoderm are apposing, and the surface ectoderm has formed a sphere. Note that this part will become the optic nerve 21 Eye embryology made simply ridiculous Note that the surface ectoderm re-establishes a continuous body wall The re-established surface ectoderm will eventually give rise to a number of eye-related structures: This process of 1) Epithelium of the conjunctiva invagination/following2) Epithelium of the cornea continues… 3) Eyelids and continues… 4) Lacrimal gland until the two walls of neuroectoderm are apposing, and the surface ectoderm has formed a sphere. Note that this part will become the optic nerve 22 Eye embryology made simply ridiculous The pinched-off sphere forms the lens vesicle 23 Eye embryology made simply ridiculous The pinched-off sphere forms the lens vesicle 24 Eye embryology made simply ridiculous The pinched-off sphere forms the lens vesicle The invaginated neuroectoderm gives rise to the: 1) Neurosensory retina 2) RPE 3) Ciliary-body epithelium (both pigmented and nonpigmented layers) 4) Iris epithelium (posterior) 5) Pupillary sphincter muscle 6) Pupillary dilator muscle 25 Eye embryology made simply ridiculous The pinched-off sphere forms the lens vesicle The invaginated neuroectoderm gives rise to the: 1) Neurosensory retina 2) RPE 3) Ciliary-body epithelium (both pigmented and nonpigmented layers) 4) Iris epithelium (posterior) 5) Pupillary sphincter muscle 6) Pupillary dilator muscle 26 Eye embryology made simply ridiculous The pinched-off sphere forms the Note that the embryology explains why thelens neurosensory retina is upsideupside downdown in the eye. vesicle The invaginated neuroectoderm gives rise to the: 1) Neurosensory retina 2) 3) Ciliary-body epithelium (both pigmented and nonpigmented layers) 4) 5) Pupillary sphincter muscle 6) Pupillary dilator muscle 27 Eye embryology made simply ridiculous The pinched-off sphere forms the lens vesicle The invaginated neuroectoderm gives rise to the: 1) Neurosensory retina 2) RPE 3) Ciliary-body epithelium (both pigmented and nonpigmented layers) 4) Iris epithelium (posterior) 5) Pupillary sphincter muscle 6) Pupillary dilator muscle 28 Eye embryology made simply ridiculous The pinched-off sphere forms the lens vesicle The invaginated neuroectoderm gives rise to the: 1) Neurosensory retina 2) RPE 3) Ciliary-body epithelium (both pigmented and nonpigmented layers) 4) Iris epithelium (posterior) 5) Pupillary sphincter muscle 6) Pupillary dilator muscle 29 Eye embryology made simply ridiculous The pinched-off sphere forms the lens vesicle The invaginated neuroectoderm gives rise to the: 1) Neurosensory retina 2) RPE 3) Ciliary-body epithelium (both pigmented and nonpigmented layers) 4) Iris epithelium (posterior) Note also that the embryology explains why the RPE and receptor(This cells part are becomes arranged the optic nerve) 5) Pupillary sphincter muscle apex-to-apex 6) Pupillary dilator muscle 30 Eye embryology made simply ridiculous Also, the embryology explains why rhegmatogenous retinal detachments occur. The neurosensory retina and RPE are not attached to one another, but rather are separated by a potential space—the remnant of the space contained within the optic vesicle. Breaks in the retina allow syneretic vitreous to gain access to this space—and the result is a rhegmatogenous RD. The pinched-off sphere forms the lens vesicle The invaginated neuroectoderm gives rise to the: 1) Neurosensory retina 2) RPE 3) Ciliary-body epithelium (both pigmented and nonpigmented layers) 4) Iris epithelium (posterior) 5) Pupillary sphincter muscle 6) Pupillary dilator muscle 31 Eye embryology made simply ridiculous What does rhegmatogenous mean in this context? It means ‘associated with a break or tear’ Also, the embryology explains why rhegmatogenous retinal detachments occur. The neurosensory retina and RPE are not attached to one another, but rather are separated by a potential space—the remnant of the space contained within the optic vesicle. Breaks in the retina allow syneretic vitreous to gain access to this space—and the result is a rhegmatogenous RD. The pinched-off sphere forms the lens What does syneretic mean in this context? vesicle It means ‘liquified’ The invaginated neuroectoderm gives rise to the: 1) Neurosensory retina 2) RPE 3) Ciliary-body epithelium (both pigmented and nonpigmented layers) 4) Iris
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