Eye anatomy

Source: Wikipedia. Pages: 73. Chapters: Retina, Iris, Pupil, Epicanthic fold, Photoreceptor cell, Tapetum lucidum, Lens, Photosensitive ganglion cell, Cornea, Eyelid, Extraocular muscles, Rod cell, Fovea centralis, Cone cell, Ciliary muscle, Retinal ganglion cell, Eyebrow, Corneal endothelium, Superior oblique muscle, Sclera, Lacrimal gland, Eyelash, Aqueous humour, Retina bipolar cell, Optic disc, Choroid, Retina horizontal cell, Muscles of orbit, Vitreous humour, Trochlea of superior oblique, Retinal pigment epithelium, Inferior oblique muscle, Conjunctiva, Levator palpebrae superioris muscle, Uvea, Retina amacrine cell, Macula of retina, Meibomian gland, Ciliary body, Annulus of Zinn, Blood-ocular barrier, Trabecular meshwork, Iris dilator muscle, Palpebral fissure, Tenon's capsule, Fundus, Corneal epithelium, Descemet's membrane, Iris sphincter muscle, Bowman's membrane, Orbital septum, Nerve fiber layer, Medial rectus muscle, Bruch's membrane, Inferior rectus muscle, Lateral rectus muscle, Superior rectus muscle, Inner nuclear layer, Stroma of cornea, Iris pigment epithelium, Tarsus, Anterior chamber of eyeball, Schlemm's canal, Outer nuclear layer, Nasolacrimal duct, Giant retinal ganglion cells, Vitreous membrane, Ciliary processes, Canthus, Corneal limbus, Anterior segment of eyeball, Lacrimal sac, Posterior segment of eyeball, Plica semilunaris of conjunctiva, Lacrimal canaliculi, Zonule of Zinn, Hyaloid canal, Lacrimal apparatus, Lacrimal punctum, Lacrimal lake, Ganglion cell layer, Outer plexiform layer, External limiting membrane, Ora serrata, Posterior chamber of eyeball, Inner plexiform layer, Episcleral layer, Medial palpebral ligament, Stroma of iris, Fibrous tunic of eyeball, Suprachoroid lamina, Scleral spur, Lacrimal papilla, Capsule of lens, Orbital fascia, Inner limiting membrane, Layer of rods and cones, Lacrimal caruncle, Capillary lamina of choroid, Ophthalmic veins, Pars ciliaris retinae, Sattler's layer, Posterior pole, Schwalbe's line, Pars plana, Tunica vasculosa lentis, Vitreous chamber, Pars palpebralis. Excerpt: The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses. These are sent to various visual centers of the brain through the fibers of the optic nerve. In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, so the retina is considered part of the central nervous system (CNS). It is the only part of the CNS that can be visualized non-invasively. The retina is a layered structure with several layers of neurons interconnected by synapses. The only neurons that are directly sensitive to light are the photoreceptor cells. These are mainly of two types: the rods and cones. Rods function mainly in dim light and provide black-and-white vision, while cones support daytime vision and the perception of colour. A third, much rarer type of photoreceptor, the photosensitive ganglion cell, is important for reflexive responses to bright daylight. Neural signals from the rods and cones undergo processing by other neurons of the retina. The output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve. Several important features of visual ...