eyebrow
each shades the eye
upper and lower eyelids
protect the eyes from injury, sunlight, and drying
eyelashes
shield the eyes
conjunctiva
produces mucous that prevents the eyes from drying
extrinsic eye muscles
moves the eyes, help maintain the shape of the eyes, and hold the eyes in the orbits
lacrimal gland
produces lacrimal secretions
lacrimal sac
passageway for tears
nasolacrimal duct
passageway for tears
fibrous tunic consists of
the sclera and the cornea
what protects internal structures, maintains the shape of the eyeball, provides a sturdy site for the attachment of extrinsic eye muslces, commonly called the white of the eye
sclera
cornea
refracts light
wha tis in the vascular tunic
iris, pupil, ciliary body, choroid
iris
regulates the size of a pupil; smooth muscle
pupil
passageway for light
ciliary body
regulates lens shape and secretes aqaueous humor; smooth muscle
choroid
absorbs light rays
produces signals in response to light
retina or nervous tunic
optic nerve
signals about vision travel along it to the optic chiasm
fibrous tunic is composed of what
dense connective tissue
optic nerve CNII
signals about vision travel along optic chiasm
lens
refracts light as it passes through ; avascular
aqueous humor
maintains intraocular pressure, eye shape, provides nutrition for the lens and cornea
vitreous humor
transmits light, holds the retina against the choroid, contributes to intraocular pressure
external ear consist of
auricle and acoustic meatus
auricle
collects sound waves and directs them into the external acoustic meatus
-composed of skin and elastic cartilage
external acoustic meatus
- passageway for sound waves
- porton of tunnel is elastic cartilage other portion is bone both are lined with skin
tympanic membrane
- commonly called eardrum
- connective tissue
- sound waves cause it to vibrate which moves the auditory ausicles
auditory ossicles
-amplify and transmit vibrations to the internal ear
malleus
- lateral ossicle
- attaches to tympanic membrane
- articulates with the incus
incus
middle ossicle
-articulates with the malleus and stapes
stapes
medial ossicle
-articulates with the incus and attaches to the oval window
pharyngotympanic tube
- opens when swallowing or yawning
- causes air pressure in the middle ear to be equal to the pressure of the atmospheric air
bony labyrinth
vestibule, semicircular canal, cochlea
vestibule
contains the membranous labyrinth
oval window
transmits the vibrations of the ossicles to the perilymph
semicircular canal
contain the membranous labyrinth
cochlea
contains membranous labyrinth
round window
a safety valve that prevents rupture of the cochlear duct
scala vestibuli
- upper tube
- contains perilymph
- part of the bony labyrinth
vestibular membrane
separates the scala vestibule and the cochlear duct
-part of the bony labyrinth
cochlear duct
middle tube
- contains endolymph
- part of the membranous labyrinth
tectorial membrane
overlies the spiral organ
spiral organ
- sits on the basilar membrane
- sensory receptors for hearing are located here
basilar membrane
separates the cochlear duct and scala tympani
scala tympani
lower tube
- contains perilymph
- part of the bony labyrinth
semicircular canal contains what
perilymph
semicircular duct contains what
endolymph
ampulla
contains the sensory receptors for equilibrium
vestibule contains what
contains perilymph
utricle is part of the _____ labirynth and contains what
membranous labyrinth
-contains endolymph and sensory receptors for equilibrium
saccule; what labirynth and contains what
- membranous
- contains endolymph and sensory receptors for equilibrium
cranial nerve 8
carries signals from the inner ear to the brain
vestibular nerve
carries signals from the utricle, saccule, and semicircular ducts to the brain
cochlear nerve
carries signals from the cochlea to the brain
