Physiology of hearing and balance Flashcards
Of the external ear/middle ear/inner ear, what is the sound collector?
External ear
Of the external ear/middle ear/inner ear, what is the mechanical force amplicator?
Middle ear
Of the external ear/middle ear/inner ear, what is the sound tranducer/analyser?
Inner ear
Middle C = ___Hz
250Hz
High C = ____Hz
500Hz
What range of hertz can humans percieve?
20Hz-20,000Hz
greater than this is “ultrasound” which some mammals can percieve
What is impedance matching?
In order to overcome this mismatch in the impedance of air and fluid, the middle ear is interposed between the tympanic membrane and the oval window.
From air –> to liquid.
More energy is required to move liquid molecules than air molecules.
Malleous is longer and that leads to pressure gain as it actss as a lever
What connects nasopharynx into middle ear?
Eustachian tube
Why does th eustachian tube let a small amount of air intot eh middle ear?
to equalise pressure witht the uter ear
Dysfunction of the eustachian tube leads to…
Middle ear negative pressure
What is the resting state of the cartilaginous part of eustachian tube? (open/closed)
Closed
opened by tensor veli palatini and levator palatine muscles
The eustachian tube is a _______ pathway for middle ear mucosa
Ventilation
How do the oval and round window work?
In phase movements
As one goes in the other goes out in sync
Two openings of the cochlea to the middle ear
Oval above round
Permit transmission of pressure wave in enclosed canal and vibration of the basilar membrane
Which membrane in the ear is the one which vibrates?
Basalar membrane
How many turns in the inner ear?
2.5
What is the central bit of innier ear called?
Modeolous
What is the function of the Inner hair cells in organ of corti?
Sound perception, sends afferents into the brain
What is the function of the outer hair cells in organ of corti?
Regulatory function, recieve afferent from the brain
At basal area - ____ frequency hearing
At apex - ____ frquency hearing
At basal area - high frequency hearing
At apex - low frquency hearing
What are Brodman areas?
Particular parts of the brain that have particular functions
Impulses, fired by organ of corti travel up which cranial nerve?
CN VIII (vestibulocochlear)
Where does depolarisattion occur?
Organ of corti
What are the three semicircular canals called?
Lateral
Poterior
Superior
