The Eyes and Ears MT 11
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Transcript The Eyes and Ears MT 11
Special Senses: The Eyes and Ears MT
Ch. 11
Adonis K. Lomibao
11/23/11
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 Eyes
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 maculaloss of central vision.
Conjunctivitis
Cataract
Central Vision Loss
Peripheral Vision Loss
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.
Structures
Common Conditions
Impacted Cerumen
Otitis-inflammation of the ear
Vertigo- whirling, dizzynesss, loss of balance
Tinnitus-a ringing, buzzing, or roaring sound in
ears.
Impacted Cerumen