Exam 2: Ear Flashcards
Auricle
Elastic cartilage
localizes and amplifies sound
External acoustic meatus
Lateral 1/3 cartilage, Medial 2/3 temporal bone
Tympanic membrane
External surface - thin epidermis
Internal surface - simple squamous to simple cuboidal epithelium (mucous membrane of middle ear cavity)
Collagen and elastic fibers radially and circularly arranged with fibroblasts - repair
Middle ear function
convert sound waves into mechanical vibrations
Middle ear is lined with
simple squamous epithelium
Loss of function of middle ear causes
conductive hearing loss
Stapes
bone attached to oval window
Attenuation reflex
with tensor tympani protects internal ear from damaging loud sounds
Otosclerosis
bone remodeling causing Stapes to be fixed onto oval window
Auditory tube
connects middle ear to nasopharynx
Lined with pseudostratified columnar epithelium with goblet cells
Equalizes pressure in middle ear
Mastoid air cells
located within mastoid process of temporal bone
lined with simple squamous epithelium
Endolymphatic space
within membranous labyrinth
Contains endolymph fluid - high in K, low Na
Perilymphatic space
between membranous and bony labyrinth
Contains perilymph fluid, high in Na, low K
Cortilymphatic space
within tunnels of organ of Corti in chochlea
contain cortilymph high in Na, low in K
Hair cells
mechanoelectric transducers
Type I hair cells
cup-shaped ending surrounding base of cell
Type II hair cells
many afferent endings
Cristae Ampullaris
sensory receptor within ampulla of semicircular ducts
Detects angular movement of head
Cupula - gelatinous protein attached to hair cells of each crista
Macula of utricle and saccule
Utricle (horizontal plane) and saccule (verticle plane)
Hair cells have sterocilia and one kinocilium
Sense linear movement of head
Cochlear duct (Scala media)
filled with endolymph
contains organ of Corti
ends at Helicotrema
Scala vestibuli
above cochlear duct
starts at oval window
filled with perilymph
Scala tympani
below cochlear duct
ends at round window
filled with perilymph
Vestibular (Reissner’s) membrane
Separates cochlear duct from Scale vestibuli
Roof of Scala media
Two layers of squamous epithelium - tight junctions
Stria vascularis
Produces endolymp
in Scala media
Basilar membrane
floor of Scala media
supports organ of Corti
Organ of Corti
contains inner and outer hair cells - made of sterocilia, no kinocilium
Inner and outer phalangeal cells
Contain cortilymph
Hair cells rest on top of phalangeal cells
Pillar cells
inner spiral tunnel
Tectorial membrane
Collagen type II, V, and IX
glycoproteins otogelin and tectorin
attaches to hair cells by stereocilia
