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Chapter 14. Ocular System. Eye: structure for sight Extraocular: outside the eye Intraocular: inside the eye Periocular: around the eye. Ocular Accessories (Adnexa/Stroma). Orbit: bony cavity of skull, eye held here Eye muscles: work together for Binocular 7 major muscles per eye
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Ocular System • Eye: structure for sight • Extraocular: outside the eye • Intraocular: inside the eye • Periocular: around the eye
Ocular Accessories (Adnexa/Stroma) • Orbit: bony cavity of skull, eye held here • Eye muscles: work together for Binocular • 7 major muscles per eye • 2 oblique, 4 rectus, retractor bulbi • 6 Extrinsic muscles provide attachment • Eyelids, Canthus (angle where eyelids meet), Tarsal plate (upper n lower eyelids), Meibomian glands, eyelashes, conjuctiva (mucous membrane that lines under side of each eyelid), Lacrimal apparatus (produce/store/ remove tears)
Eyeball / Globe • Sclera: fibrous outer layer of eye (white of the eye) • Anterior portion = cornea • Choroid: opaque middle layer of the eye (not light passage) • Pupil : Central circular opening • Lens: clear flexible curved capsule located behind the iris and pupil, Adjusts (accommodates) to see near/far • Ciliary Body: thickened extension of choroid to aid in accommodation • Iris: “Colored portion”, contains muscles that contract pupil in response to light
Eye Contin: • Retina: nerve tissue layer that receives images
Vision • Accommodation: Distance • Refraction: Lens bends rays of light to help focus • Convergence: simultaneous inward movement in both eyes, normally happens as an object moves closer • Acuity: sharpness of vision
Common Tests: Eyes • PLR: pupillary light reflex: animal’s response to light • Flourescein: dye on the surface to detect corneal injury • Menace Response: eye should close as object moves towards it • Palpebral reflex: blink in response to eye being touched • Schirmer tear test: graded paper slip measures tear production
Common Ailments: • Anisocoria: unequal pupil size • Blepharitis: inflammation of eyelid • Blepharoptosis: dropping of eyelid • Cataract: cloudiness of eye • Entropin: inturning of eyelid • Strabismus: “cross eyed”
Common Procedures: Eyes • Common prefixes • Oplasty: surgical repair • Ectomy: removal • Otomy: incision • Centesis: removal of liquid (to relieve pressure)
EARS: Structures • Outer Ear • Pinna: external portion that catches sounds waves • Middle Ear • Eardrum: tissue separating external from middle ear • Auditory ossicles: ear bones • Malleus, incus, stapes • Eustachin tubes • Oval window: separates middle from inner ear • Round window: membrane receives sound waves • Tympanic bulla: located at base of skull
EAR Structures Continued: • Inner Ear • Bony Labrinth • Vestibule: balance and position • Semicircular canals: hairlike structures help with spacial awareness • Cochlear: recieves and transmits sound waves to the brain
Testing Ears • Otoscopy: exam for parasites • Otoscope: Tool used for otoscopy
Pathology • Otalgia: ear pain • Deafness: hearing loss • Otomycosis: fungal infection of the ear • Otopyorrhea: pus discharge from ear
Activities • Diagram of Eye (pg 292) and Ear (pg 299) • Outline of Sight (pg 291-292) and Sound (pg 300) • Explain balance, and how the body reacts to changes