Special Senses Flashcards
consists of the auricle and external auditory meatus
external ear
the pinna or fleshy part of the ear whose cartilaginous framework gives it shape fro capturing sound waves
auricle
a tube approximately one inch long that directs sound waves from the external environment to the tympanic membrane
external auditory meatus
contains the auditory ossicles and associated structures within the tympanic cavity
middle ear
a membranous structure separating the middle and external ear, vibrates in response to sound waves
tympanic membrane
three small bones of the middle ear that receive vibrations from the tympanic membrane and transmit them to the oval window
auditory ossicles
most lateral ossicle, the head of which is rounded, attached to the tympanic membrane
malleus
middle ossicle, has a wide body and is “y” shaped
incus
most medial ossicle that attaches to the oval window
stapes
a skeletal muscle that runs along the auditory tube and inserts on the malleus, its action protets the hearing receptors of the inner ear by reducing possible movement of bone.
tensor tympani muscle
membranous partition between the middle and inner ear to which the stapes wone attaches; relays soundwaves to the vestibular duct
vestibular (oval) window
membranous partition covering a circular opening between the inner and middle ear and inferior to the oval window.
cochlear (round) window
an elongated tube that joins the tympanic cavity of the middle ear with the nasopharynx; opening it equalizes the pressure on both sides of the tympanic membrane necessary for it to function properly, allows for easy passage of bacteria and infection thus earaches and sore throats go together frequently
auditory (eustachian) tube
composed of a bony labyrinth cavity that houses the cochlea and vestibule
inner ear
a branch of the vestibulocochlear nerve VIII that arises from the hair cells of the vestibule of the inner ear, transmits impulses of balance to the brain
vestibular nerve
bony, tube-like structures connected to the vestibule with each canal lying in one of the three planes of space; respond to rotational movement and maintain balance
semicircular canals
a spiral tube whose inner ear chamber is divided into three compartments
cochlea
a branch of the vestibulocochlear nerve VIII that arises from the spiral organ of Corti which transmits impulses of hearing to the brain
cochlear nerve
superior chamber of cochlea that receives sound waves from the oval window; filled with perilymph
scala vestibuli
within the cochlea, this membrane separates the scala vestibuli from the cochlear duct
vestibular membrane
inferior chamber of the cochlea filled with perilymph
scala tympani
floor of cochlear duct, separates cochlear duct form scala tympani
basilar membrane
fluid contained within the scala vestibuli and the scala tympani of the cochlea
perilymph
the middle chamber of the cochlea filled with endolymph and contains the spiral organ of Corti, the fuctional unit for sensory response to sound vibrations
cochlear duct
fluid contained in the cochlear duct
endolymph
functional unit of hearing, located within the cochlear duct, contains cochlear hair cells and supporting cells
spiral organ of corti
serve as sound receptors in the basilar membrane
cochlear hair cells
located within the cochlear duct, associated with the tips of the hairs of the organ of corti
tectorial membrane
composed primarily of skeletal muscle attached to the hyoid bone, it pushes food against the palate to turn it into a bolus
tongue
connects the tongue to the floor of the oral cavity
lingual frenulum
provides a rough surface on the tongue for manipulating food, taste buds are intermingled with the papillae
papillae
the smallest and the most numerous papillae found on the anterior 2/3 of the tongue
filiform papillae
intermediate size papillae scattered among the filiform papillae
fungiform papillae
the largest of the papillae located on the back of the tongue
circumvallate papillae
moveable eyelid bearing eyelashes to prevent objects from injuring the eye
palpebrae
the muscle that elevates the upper eyelid, origin is the orbit
levator palpebrae superioris
located within the upper and lower eyelids, secrete oily fluids that prevent the eyelids from sticking together
tarsal glands
located superior and slightly lateral to the eye, secretes fluid (tears) that contains an enzyme that prevents infection
lacrimal gland
several small ducts that drain lacrimal fluid from the lacrimal glands into the conjunctival sac of the upper eyelids
excretory lacrimal ductules
fleshy elevation within the medial angle of the eye that produces a whitish secretion
caruncle
tiny opening in the superior and inferior palpebrae at the outer edge of the medial angle; allows tears to drain from the eyes into the lacrimal canals
lacrimal punctum
drain tears form medial angle of eye to nasolacrimal duct
lacrimal canals
sac located in the medial orbital walls that receives lacrimal fluid directly form the lacrimal canals
lacrimal sac
drains fluid form the lacrimal sac to the nasal cavity
nasolacrimal duct
located beneath the levator palpebrae superioris; adducts, elevates, and medially rotates eye
superior rectus
muscle that passes through the trochlea and inserts on the posterolateral surface of the eye; abducts, depresses and medially rotates eye. Innervated by trochlear nerve IV.
superior oblique
a looplike structure on the inner, upper part of the orbit of the eye through which the superior oblique muscle passes.
trochlea
muscle located on the medial side of the eye; adducts eye
medial rectus
muscle located on the inferior part of the eye; adducts, depresses and laterally rotates eye
inferior rectus
muscle located on the inferior side of eye; abducts, elevates and laterally rotates eye
inferior oblique
muscle located on the lateral side of the eye; abducts eye. Innervated by abducens nerve VI
lateral rectus
outermost, white layer of the eye
sclera
a protective mucous membrane hat lines the inner surface of the eyelid and white outer surface of the eye
conjunctiva
the transparent fibrous covering of the anterior portion of the eye, allows light to enter eye
cornea
the middle layer of the wall of the eye, containing blood vessels that supply the other avascular layers of the eye
choroid
the enlarged anterior portion of the choroid that contains smooth muscle and attaches to and controls the shape of the lens by way of suspensory ligaments; posterior to the iris
ciliary body
fibers that bridge between the ciliary muscle and the lens of the eye
ciliary zonules (suspensory ligament)
colored, smooth muscular extension of the choroid that regulates the diameter of the pupil
iris
jagged margin between the photosensitive posterior region of the retina and the nonphotosensitive anterior region of the retina that covers ciliary body
ora serrata
opening in anterior part of eye surrounded by iris; allows light to enter eye
pupil
located posterior to the iris and pupil, refracts light, focuses visual objects on the fovea centralis and other part of the retina
lens
sensory membrane located in the innermost layer of the wall of the eye, contains rods and cones for photoreception
retina
area with an abundance of cones that surrounds the fovea centralis
macula lutea
a small region in the retina where cones are concentrated for highly efficient vision, located in the center of the macula lutea
fovea centralis
region of the eye where the optic nerve enters and photoreceptors are absent, known as the “blind spot”
optic disc
transmits impulses form the retina to the brain
optic nerve II
the portion of the anterior segment located between the iris and the cornea, filled with aqueous humor
anterior chamber
the portion of the anterior segment located between the iris and the lens, filled with aqueous humor
posterior chamber
fluid that fills the anterior and posterior chambers, this fluid helps maintain intraocular pressure
aqueous humor
the posterior segment of the eye located between the posterior side of the lens and retina, filled with vitreous humor
vitreous chamber
viscous fluid that fills the vitreous chamber of the eye, provides intraocular pressure
vitreous humor
