200 likes | 398 Views
Adonis K. Lomibao 11/23/11. Special Senses: The Eyes and Ears MT Ch. 11. Objectives. Identify the basic function and structures of the Eyes. Identify the basic function and structures of the Ears. The Eyes. Function- receive images and transmit them to the brain.
E N D
Adonis K. Lomibao 11/23/11 Special Senses: The Eyes and Ears MT Ch. 11
Objectives • Identify the basic function and structures of the Eyes. • Identify the basic function and structures of the Ears.
The Eyes • Function- receive images and transmit them to the brain. • Structures include the eyeball and adnexa
The Adnexa of the Eyes • The structures outside of the eyeball • They include the: Orbit (eye socket), eye muscles, eyelids, eyelashes, conjunctiva, and lacrimal apparatus. • Adnexa-means appendages or accessory structures of an organ. Lacrimal Apparatus:produce, store, and remove tears
The Eyeball • Aka globe, 1-inch sphere with only 1/6 of surface visible. • Sclera: (whites of the eye) maintains shape and protects inner tissue. • Choroid:middle layer, vascular: provides blood supply for eye. Retina:converts light images into electrical impulses and transmits them to the brain.
The Uveal Tract • The pigmented layer of the eye. • Consists of the: -Choroid:provides blood supply for the eye. -Ciliary body:in the choroid-muscles and ligaments that adjust the thickness of the lens to refine focus of light rays on the retina. -Iris:controls the amount of light entering the eye.
Cornea, Pupil, Lens • Cornea: transparent outer surface—focuses light rays entering the eye. • Pupil: the black circular opening in the center of the iris that permits light to enter the eye. • Lens: clear, flexible, curved structure that focuses images on the retina.
Common Conditions • Conjunctivitis (pink eye)-inflammation of the conjunctiva • Corneal abrasion-a scratch or irritation to the outer layers of the cornea • Cataract-loss of transparency of the lens • Glaucoma-increased intraocular pressure • Macular degeneration-damage of the macula-loss of central vision.
Refractive Disorders • Focusing problem that occurs when the lens and cornea do not bend light so it focuses properly on the retina. • Astigmatism-impoper focus due to uneven curvatures of the cornea • Hyperopia-(farsightedness) light rays focus beyond retina • Myopia-(nearsightedness) light rays focus in front of the retina
The Ears • Function- receive sound impulses and transmit them to the brain • Auditory-pertaining to the sense of hearing • Acoustic-relating to sound or hearing
Major structures • The outer ear-includes the pinna, the external auditory canal, & cerumen. • The middle ear- transmits sound to the inner ear. Includes the tympanic membrane or eardrum. • The inner ear- contains sensory receptors for hearing and balance.
Common Conditions • Impacted Cerumen • Otitis-inflammation of the ear • Vertigo- whirling, dizzynesss, loss of balance • Tinnitus-a ringing, buzzing, or roaring sound in ears.