Functions of the basilar membrane
- Dashboard
- Functions of the basilar membrane
Most Recent Score Report
| Questions Correct | Questions Answered | Time Spent | Status | Attempt Date | |
|---|---|---|---|---|---|
| -- | -- | -- | -- | -- |
Previous Score Reports
| Questions Correct | Questions Answered | Time Spent | Status | Attempt Date | |
|---|---|---|---|---|---|
| -- | -- | -- | -- | -- |
Functions of the basilar membrane
Array
(
[passage] => WP_Post Object
(
[ID] => 558929
[post_author] => 12815
[post_date] => 2024-12-26 10:59:49
[post_date_gmt] => 2024-12-26 15:59:49
[post_content] => Practice Passage (Question 1-5)
*This passage is the property of Khan Academy and has been reformatted into an AAMC-style interface in their entirety by MedLife Mastery. MedLife Mastery does not endorse and is not an affiliate of Khan Academy.
The basilar membrane sits inside of the cochlea, and contains over 10,000
sensory hair cells that project axons into what eventually becomes the auditory nerve. The basilar membrane varies in stiffness, and is stiffest nearest the oval window, and floppiest near the apex. This allows it to function as a frequency spectrum analyzer. When exposed to a high frequency signal, the basilar membrane resonates where it is stiff, resulting in the excitation of nerve cells close to the oval window. Likewise, low frequency sounds excite nerve cells at the far end of the basilar membrane. This makes specific fibers in the cochlear nerve respond to specific frequencies. This organization is called the place principle, and is preserved throughout the auditory pathway into the brain.
Another information encoding scheme is also used in human hearing, called the volley principle. Nerve cells transmit information by generating brief electrical pulses called action potentials. A nerve cell on the basilar membrane can encode audio information by producing an action potential in response to each cycle of the vibration. For example, a 200-hertz sound wave can be represented by a neuron producing 200 action potentials per second. However, this only works at frequencies below about 500 hertz, the maximum rate that neurons can produce action potentials. The human ear overcomes this problem by allowing several nerve cells to take turns performing this single task. For example, a 3000-hertz tone might be represented by ten nerve cells alternately firing at 300 times per second. This extends the range of the volley principle to about 4 kHz, above which the place principle is exclusively used. (Adapted from: https://www.dspguide.com/ch22/1.htm)
[post_title] => Functions of the basilar membrane
[post_excerpt] =>
[post_status] => publish
[comment_status] => closed
[ping_status] => closed
[post_password] =>
[post_name] => functions-of-the-basilar-membrane
[to_ping] =>
[pinged] =>
[post_modified] => 2024-12-26 10:59:49
[post_modified_gmt] => 2024-12-26 15:59:49
[post_content_filtered] =>
[post_parent] => 0
[guid] => https://medlifemastery.com/?post_type=passage&p=558929
[menu_order] => 0
[post_type] => passage
[post_mime_type] =>
[comment_count] => 0
[filter] => raw
)
[questions] => Array
(
[0] => Array
(
[quiz_unique_key] => 578908434
[question] => If the distal half of the basilar membrane was damaged, what symptoms would be expected in an affected individual?
[value] => Array
(
[answer] => 2
[description] => Reason for the Correct Answer:
The proximal part of the basilar membrane is sensitive to high frequency sounds.
The distal part of the basilar membrane is sensitive to low frequency sounds.
Damage to the distal basilar membrane would result in an inability to hear sounds of low frequency.
)
[answers] => Array
(
[0] => Array
(
[each_answer] => A. Inability to hear sounds of very high frequencies.
)
[1] => Array
(
[each_answer] => B. Inability to hear sounds of very low frequencies.
)
[2] => Array
(
[each_answer] => C. Ability to hear low frequency sounds.
)
[3] => Array
(
[each_answer] => D. Inability to discriminate between high frequency sounds.
)
)
)
[1] => Array
(
[quiz_unique_key] => 3873426850
[question] => The basilar membrane has thousands of hair cells that are each sensitive to sound waves of a particular frequency, how does this contribute to the ability to discriminate between different sounds?
[value] => Array
(
[answer] => 1
[description] => Reason for the Correct Answer:
Signals from the hair cells within the cochlea eventually reach the primary auditory cortex.
A tonotypical map represents sound while a topographical map represents position.
Since the primary auditory cortex is responsible for receiving input from various frequency sensitive hair cells, it contains a tonotypical map that allows the brain to distinguish between sounds.
)
[answers] => Array
(
[0] => Array
(
[each_answer] => A. A tonotypical map on the primary auditory cortex preserves the frequency discrimination at the level of the basilar membrane.
)
[1] => Array
(
[each_answer] => B. A topographical map on the primary auditory cortex preserves the frequency discrimination at the level of the basilar membrane.
)
[2] => Array
(
[each_answer] => C. A tonotypical map on the secondary auditory cortex preserves the frequency discrimination at the level of the basilar membrane.
)
[3] => Array
(
[each_answer] => D. A topographical map on the secondary auditory cortex preserves the frequency discrimination at the level of the basilar membrane.
)
)
)
[2] => Array
(
[quiz_unique_key] => 83407773
[question] => Which of the following is correct with regards to the transduction of a sound wave into an electrical impulse?
[value] => Array
(
[answer] => 2
[description] => Reason for the Correct Answer:
The cochlea is a fluid filled structure containing the organ of corti (which contains many sensory hair cells that respond to fluid movement).
Human ears are sensitive to sounds between 20 – 20,000 Hz.
Since the organ of corti is within the cochlea and is responsible for transducing fluid movement (caused by bones of the inner ear pressing against the oval window), it is essential for proper audition.
)
[answers] => Array
(
[0] => Array
(
[each_answer] => A. The sound wave causes air within the cochlea to stimulate sensory hair cells.
)
[1] => Array
(
[each_answer] => B. The organ of corti is responsible for transducing fluid movement within the cochlea into an electrical impulse.
)
[2] => Array
(
[each_answer] => C. The kinocillia attached to hair cells within the tympanic membrane respond to fluid movement caused by pressure waves.
)
[3] => Array
(
[each_answer] => D. The ear is not sensitive to sounds with a frequency higher than 5,000 Hz.
)
)
)
[3] => Array
(
[quiz_unique_key] => 2261298308
[question] => What would occur if the eardrum was ruptured?
[value] => Array
(
[answer] => 3
[description] => Reason for the Correct Answer:
The tympanic membrane (eardrum) is connected to the oval window via the malleus, incus, and stapes.
Tympanic membrane rupture would result in severely damped oscillation of the malleus, incus, and stapes.
The oval window would thus vibrate less.
)
[answers] => Array
(
[0] => Array
(
[each_answer] => A. The round window would also eventually rupture
)
[1] => Array
(
[each_answer] => B. The tympanic membrane would still function as normal.
)
[2] => Array
(
[each_answer] => C. Oval window vibrations would be severely dampened.
)
[3] => Array
(
[each_answer] => D. The malleus, incus, and stapes would function as normal.
)
)
)
[4] => Array
(
[quiz_unique_key] => 4015992898
[question] => What are the various structures of the ear that a sound wave has to pass through to reach the cochlea?
[value] => Array
(
[answer] => 4
[description] => Reason for the Correct Answer:
Pinna = fleshy, visible part of outer ear; Tympanic membrane = eardrum
The oval window connects the stapes to the cochlea.
The correct order of bones from the tympanic membrane to the oval window is malleus, incus, stapes.
)
[answers] => Array
(
[0] => Array
(
[each_answer] => A. Pinna, auditory canal, tympanic membrane, incus, malleus, stapes, round window
)
[1] => Array
(
[each_answer] => B. Pinna, auditory canal, tympanic membrane, incus, malleus, stapes, oval window
)
[2] => Array
(
[each_answer] => C. Pinna, auditory canal, tympanic membrane, malleus, incus, stapes, round window
)
[3] => Array
(
[each_answer] => D. Pinna, auditory canal, tympanic membrane, malleus, incus, stapes, oval window
)
)
)
)
[total_question] => 5
[correct_answers] => Array
(
[558929|1] => B
[558929|2] => A
[558929|3] => B
[558929|4] => C
[558929|5] => D
)
[hide_display_feedback_settings] =>
[hide_solutions] =>
)