23-24 - Hearing Flashcards
Sound is defined by two properties…
- Frequency (the pitch, measured in hertz (Hz) which is the cycles per second) 2. Amplitude (the intensity, measured in decibels (dB))
The range of audible frequencies (for a young person) is…
20Hz to 21 kHz
The outside part of the ear (👂) is called the…
Pinna
The pinna helps…
In locating the position of a sound (on the vertical plain)
The auditory canal is a tube which separates the pinna and the middle ear. What are the advantages (2) of this arrangement, instead of having the middle ear located right next to the pinna?
- Allows the delicate inner ear to be protected further inside the head 2. Amplifies sounds such as speech (resonant at 250Hz-3kHz)
How is pressure equalised between the middle ear and the outside atmosphere?
The Eustachian tube
The purpose of the middle ear is to transfer sound energy…
From one medium to another (from air to fluid)
The middle ear improves energy transfer because the tympanic membrane is A) Larger B) Smaller C) Equal in size Compared to the stapes…
A) Larger Same force, smaller area = higher pressure
The arrangement of the malleus, incus and stapes bones creates a…
Lever (Which also contributes to increased pressure)
The upper chamber inside the cochlea is the…
Scalia vestibuli
The lower chamber inside the cochlea is the…
Scalia timpani
Between the scala vestibuli and scala timpani is the…
Scala media
The spiral ganglia are the…
Cell bodies of the cochlear nerve fibres
Which statement about the perilymph is true? A) It is high in K+, found in the scala media B) It is high in Na+, found in the scala vestibuli and timpani C) It is high in K+, found in the scala vestibuli and timpani D) It is high in Na+, found in the spiral ganglia
B) It is high in Na+, found in the scala vestibuli and timpani
Endolymph is high in ( K+ / Na+ / Ca2+ ) and is found in the scala media.
K+
Excitation of the inner hair cells leads to…
Transmitter release (and excitation of auditory nerve fibres)
Inner hair cells generate ( action / graded ) potentials…
Graded potentials
Which of the following statements about outer hair cells is false? A) Release neurotransmitters B) Amplify vibrations C) Contain prestin motor proteins D) Act as cellular motors
A) Release neurotransmitters Unlike inner hair cells, outer hair cells do not Release neurotransmitters.
