Sensory organ (a) those of the special senses of taste, smell, sight, and hearing (b) those associated with the general sensations of heat, cold, pain, pressure, etc. Exteroreceptor Interoreceptor Proprioceptor

Visual organ eyeball accessory organs of eye blood vessel and nerves of eye

eyeball wall The Refracting Media

(1) A fibrous tunic, consisting of the sclera behind and the cornea in front; (2) a vascular pigmented tunic, comprising, from behind forward, the choroid, ciliary body, and iris; (3) a nervous tunic, the retina.

Fibrous tunic The Sclera The Cornea.— (1) corneal epithelium, (2) substantia proprius (3) posterior elastic lamina; (4) endothelium anterior chamber. Between this tissue and the anterior surface of the attached margin of the iris is an angular recess, named the iridial angle or filtration angle of the eye

The Vascular Tunic formed from behind forward ： choroid, the ciliary body, and the iris. The choroid: five-sixths of the bulb, The ciliary body connects the choroid to the circumference of the iris. The iris is a circular diaphragm behind the cornea, a rounded aperture, the pupil.

The Retina (tunica interna) delicate nervous membrane, outer surface is the choroid; its inner with the hyaloid membrane of the vitreous body. pars ciliaris retinæ and pars iridica retinæ Exactly in the center of the posterior, and at a point sense of vision is most perfect, is an oval yellowish area, the macula lutea; in the macula is a central depression, the fovea centralis the arteria centralis retinæ pierces the center of the disk. insensitive to light, and it is termed the blind spot.

The Refracting Media The Aqueous Humor ciliary body secretes- posterior chambers –pupil- anterior chambers - iridocorneal angle -sinus venous sclera. The Vitreous Body The Crystalline Lens (In old age it becomes flattened on both surfaces, slightly opaque, of an amber tint, and increased in density)

Accessory Organs ocular muscles the fascia, the eyebrows, the eyelids, the conjunctiva the lacrimal apparatus

Levator palpebræ superioris Rectus medialis Rectus superior Rectus inferior Obliquus inferior oculomotor nerve Rectus lateralis abducent nerve Obliquus superior trochlear nerve

lacrimal apparatus Lacrimal Gland lacrimal ducts (puncta lacrimalia, superior duct, inferior duct) Lacrimal Sac Nasolacrimal Duct (middle nasal meatus)

Vessels and Nerves arteria centralis retinæ ciliary veins Optical nerves