Download 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