Chapter 5: Diseases and Disorders of the Eye and Ear: Overview Flashcards
what is the three processes of vision
image formed on retina
rods and cones are stimulated
nerve impulses conducted to the brain
what are the three concentric layers of the eye
sclera, choroid, and the retina
tough fibrous connective tissue that is visible as the white of the eye
sclera
what layer of the eye are the six extrinsic muscles connected to
sclera
continuous with the ciliary body and the iris. vascular portion of the eye
choroid
colored portion of the eye
iris
posterior three quarters of the eye; made up of rods and cones; nervous portion of the eye
retina
function best in dim light, night vision. black and white structures
rods
function best in bright light and also detect color and fine detail
cones
contains no receptor cells and is located in the eye
optic disc “blind spot”
yellow spot, lies laterally to the optic disc.
macula lutea
in the center of the macula lutea and produces the sharpest image
fovea centralis
thin transparent membrane covers the sclera
conjunctiva
between the iris and the anterior clear cornea is called the
anterior chamber
what fluid occupies the anterior chamber
aqueous humor
what produces aqueous humor
ciliary body
large cavity behind the lens
vitreous body
what fluid occupies the vitreous body
vitreous humor
the lens is attached to the ciliary body by small strands of tissue called
zones
process of bending light rays
refraction
what two structures are responsible for refraction
cornea and lens
adjustment made in the eye to facilitate the image in relation to the viewer’s distance from the object
accommodation
eye chart that measures visual acuity
Snellen Chart
measures intraocular pressure
tonometry
secretes tears to the eye
lacrimal glands
protects the eye
eyelid
muscle rotates eyeball downward and medially; adducts;
what cranial nerve
Inferior Rectus; Oculomotor nerve (III)
rotates eye laterally; abducts eyeball;
what cranial nerve
Lateral Rectus; Abducens nerve (VI)
rotates eye medially; abducts eyeball;
what cranial nerve
Medial Rectus; Oculomotor nerve (III)
causes eye to look up;
what cranial nerve
Superior Rectus; Oculomotor nerve (III)
Rotates eyeball upward and outward; abducts;
what cranial nerve
Inferior Oblique; Oculomotor nerve (III)
Rotates eyeball downward and outward; abducts
what cranial nerve
Superior Oblique; Trochlear nerve (IV)
Regulation of lens shape for close vision
what cranial nerve
Ciliary Muscle; Oculomotor (III)
Sympathetic stimulation; dilation of pupil
what cranial nerve
Iris (radial muscles); Oculomotor (III)
Parasympathetic stimulation; contraction of pupil
what cranial nerve
iris (circular muscles); Oculomotor (III)
contraindicated in patents who suffer from heart failure; a glaucoma medication
Beta-Blockers
what are the three sections of the ear
outer, middle and inner
the outer ear is called
auricle or pinna
tympanic membrane is called
eardrum
what is in the middle ear
tympanic membrane
three auditory ossicles
what are the three auditory ossicles
malleus (hammer)
incus (anvil)
stapes (stirrup)
a tube that leads from the middle ear to the pharynx
eustachian tube
what is contained in the inner ear
cochlea and labyrinth
contains tiny hairs that change the sound waves in the fluid into nerve impulses
cochlea
is responsible for maintaining balance; the large overview structure
labyrinth
three connected tubes bent into half circles. in the labyrinth
semicircular canals
caused by impairment of the eardrum or bones in the middle ear
conductive hearing loss
results from impairment of the cochlea or the auditory nerve
sensorineural deafness
drug or chemical causes damage to the eighth cranial (acoustic) nerve or to the inner ear
ototoxicity
fluid that circulates the inner ear
endolymph
most common cause for diminished visual acuity. result in the eye being unable to focus light effectively on the retina
refractive erros
what are the 4 refractive errors of the eye
hyperopia
myopia
astigmatism
presbyopia
