The Eart Flashcards
What is the pathway for transmission of sound?
- ossicles (MIS) transmit sounds waves from ear drum to oval window
- Fluid waves travel through perilymph to round window
- Fluid waves re transmitted to endolymph-filled cochlear duct and stimulate hair cells
What makes the cerumen?
Ceruminous glands in the external acoustic meatus
What is the size of the oval window compared to the tympanic membrane?
It’s 1/18th the size
What are the effects of Ménière’s disease?
Vertigo, hearing loss, tinnitus
What is Ménière’s disease?
Malfunction of endolymphatic sac results in increase of endolymphatic volume (hydrops) and distensiones in the membranous labyrinth and cochlear duct.
What are the concentrations of endolymph?
High protein content
Low Na+ content
High K+ content
What are the ion concentration of perilymph?
High Na+
Low K+
The utricle and saccule make up what organ?
The vestibule
The cochlear duct is used for?
Hearing
The semicircular canal are used for?
Balance
How does the endolymphatic sac regulate endolymph volume?
By maintaining a high protein content, thereby creating an osmotic gradient that draws fluid into the membranous labyrinth.
What is tinnitus?
Funny sounds
What part of the vestibular system measures linear acceleration?
2 sacs:
- Utricle with macula: horizontal
- Saccule with macula: vertical
What part of the vestibular system is responsible for angular acceleration?
3 semicircular canals (ampullae with crista ampularis)
What part of the auditory system is responsible for sound perception?
Cochlear duct with organ of corti
What are otoconi?
Calcium carbonate stones used to find out which way you’re moving
What is the true cilia within the membranous labyrinth?
Kinocilium
Mechanical deformation toward the kinocilium _____ K+ channels in the sterocilia.
Open
Mechanical deformation way from the kinocilium ______ K+ channels in the sterocilia.
Closes
When K+ channels open in the kinocilium, what happens?
Ca+ enters the cell, allowing vesicles fusion and release of neurotransmitter.
Note: K+ leaves the cell via K+ channels
What do you call the bony labyrinth in the cochlea?
Scala vestibuli
Scala tympani
(Depends on what part you’re on, vestibuli is on top and tympani is on bottom)
What do you call the membranous labyrinth in the cochlea?
Scala media/cochlear duct
What type are inner and outer hair cells in the cochlea?
Inner: type 1
Outer: type 2
What are border cells? (Cochlea)
Supportive cells
What are the scala vestibuli and tympani filled with?
Perilymph high in Na+ content
What creates endolymph?
Stria vasularis
What is Stria Vasularis?
Pseudostratified epithelium
Vascular tissue
K+ homeostasis of endolymph
What separates the scala vestibuli from the cochlear duct?
Vestibular (Reissner’s) membrane
What kind hair cells are in the hearing apparatus?
Type 1 are connected to the cochlear nerve (inner)
Type 2 are arrange in rows of 3 (outer hair cells)
