Hearing Physiology Explained in Under 5 Min | Auditory Transduction & Inner Hair Cells

Ever wondered how your brain converts sound waves into meaning? This is essential knowledge for USMLE prep and medical students!

In this video, we break down the mechanisms of hearing, focusing on how inner hair cells in the cochlea translate mechanical vibrations into neural signals. Whether you're prepping for the USMLE or diving deeper into medical physiology, this concise yet high-yield breakdown will give you a clear grasp of auditory processing. Stay tuned for expert insights and mnemonics to make complex concepts effortless to remember!

In this video, we break down the mechanisms of hearing, focusing on how inner hair cells in the cochlea translate mechanical vibrations into neural signals. Whether you're prepping for the USMLE or diving deeper into medical physiology, this concise yet high-yield breakdown will give you a clear grasp of auditory processing. Stay tuned for expert insights and mnemonics to make complex concepts effortless to remember!
Auditory perception of sound and human ear sensitivity are very impressive.
Vibration of hair cells at the threshold pressure is ~ 0.1-0.3 nm, which is smaller than the diameter of an atom! And hair cells can respond more than 20000 times a second!

👉 How do we perceive sound?
In order to understand the physiological aspects of hearing, it is necessary to understand what sound is actually.

What is sound and how do we perceive it? Vibrating objects create sound waves, which are pressure waves in the air.
Once the sound waves reach the inner ear, tiny hair cells called stereocilia are mechanically deflected and caused to vibrate. They transform the vibrations (mechanical stimulus, pressure wave) into electrical energy (nerve impulse, electrical signal) and send it along nerve fibers (cochlear nerve) to the brain, which interprets the incoming signal as sound.
This process is known as auditory transduction or mechanoelectrical transduction.
Impressive sensitivity of the human ear: At a reference frequency of 1,000 Hz, the ear can detect pressure fluctuations (threshold pressure, the smallest detectable pressure change) as tiny as ~ 2 × 10-5 Pa (above and below atmospheric pressure), which is astounding. Why? Atmospheric pressure at sea level is 100000 Pa and we don’t even feel this pressure. Go figure, the human ear is able to perceive a change in the atmospheric pressure as small as ±1 part in 5,000,000,000. So small is the threshold pressure the human ear can perceive as sound.
This pressure causes vibration of hair cells in our inner ears, which are transmitted to our brain where we eventually interpret the incoming signal as sound.

The vibration (change in length) of the hair cells at the threshold pressure (the smallest fluctuations in atmospheric pressure we perceive as sound) is as tiny as 0.1-0.3 nm, which is smaller than the size of an atom!
And hair cells can respond more than 20000 times a second!

👉 Related videos you may need:
Human ear physiology | Concepts & Mechanisms of Hearing
https://youtu.be/7Xhz4smXmzg

Impedance Matching Ear Physiology | Middle ear bones
https://youtu.be/ErrYVmtfVb8

Frequency coding mechanisms in human ear | Basilar membrane & Place coding
https://youtu.be/xwvOm2OiVDo

Видео Hearing Physiology Explained in Under 5 Min | Auditory Transduction & Inner Hair Cells канала Medical Physiology: Prof. John 8-12