exuvise

(ex-u’ve-e) [L. exu’ere to strip]. 1. Castoff epidermis. 2. A slough. eye (i) [L. ocu’lus; Gr. d6¢@adpds]. The organ of vision. In shape the eye consists of a large sphere, with the segment of a smaller sphere, the cornea, in front. It is composed of three coats-- the sclerotic and cornea, the choroid, and the relinaeach coat being divided into several layers. Within the three coats are the refracting media ---namely, the aqueous humor, the crystalline lens, and the vitreous humor. The sclerotic, or external coat, is white and fibrous. Posteriorly the fibers of the optic nerve enter through small perforations in the lamina cribrosa. The inner surface is attached to the choroid by delicate connective ti ue, the lamina fusc a. The cornea is composed of five layers, the internal layer being a serous membrane, and sometimes called Descemet’s membrane. The choroid, or middle coat, is chiefly composed of blood-ve els and pigment. Anteriorly, it terminates near the periphery of the lens in folds called the ciliary proce es. The retina, or internal coat, is chiefly composed of nerve ti ue, and is made up of three principal layers. The external layer, or Jacob’s membrane, is composed of terminal nerve-cells, which, from their shape, are called the rods and cones. The iris is a curtain with a central perforation, the pupil, and is composed of smooth muscular fibers arranged both in a circular and in a radiating manner. It varies in color, and is suspended in the aqueous humer Vertical section through the eyeball: a, sclera; 6, choroid; c, ciliary muscle; d, iris; ¢, cul -de-sac of conjunctiva; /, anterior chamber; κ and humor; g. cry ine lens; ye posterior chamber; 7, angle hace ee before, the of h it, Ὑ lig: of lens; 4, cornea; 2, Steet vitreous; m, optic nerve with central artery of retina; #, retina; 0, o', ocular muscles. eyelids separated iS; Phe Pu, peri P| inferior lacrimal puncta; Car, lacrimal caruncle; Lom internal tarsal ligament. Corneal epithets: Bowman's membrane Cornea proper Descemet's membranc Corneal endothelium Sphincter of the iris Canal of Schlemm Ciliary muscle Zonule of Zinn Ciliary proce es Comparative diagram showing the change in the shape of the crystalline lens during accommodation. The right side shows the lens at rest. Diagram of the lacrimal apparatus: a, lacrimal gland; 4, tarsal cartilage; c, nasal duct; @, lacrimal canaliculus. The external ocular muscles: a, levator of upper lid; 4, superior rectus; c, external rectus; i i ς 4, inferior rectus; ¢, superior oblique; /, internal rectus; g, inferior oblique. The Dad rectus muscle; with its nerves and blood-ve els: a, section of conjunctiva; 4, sclerotic; c, cornea; @, pupil; ¢, section of superior J. inferior rectus muscle; g, external rectus muscle; 7, superior oblique muscle; 1, ophthalmic artery; 2, ophthalmic vein; 3. optic nerve; 4, ophthalmic nerve; 5, motor nerve of eye; 6, ophthalmic or lenticular ganglion. -, the affected eye in strabismus. trichromatic °. the normal eye: one in which the red, green, and blue end-organs are in a normal state. 350 FACIOCERVICAL