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In this IBDP Biology Blog post, it will highlight the structure of the ear, as well as enable us to understand how humans generally hear.
Diagram of Ear
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4979856/147203_283780.png)
How sound is perceived by the ear
1. Eardrum:
- Soundwaves reach eardrum and makes it vibrate.
- Vibration consists of rapid movements towards and away from the middle ear.
- The eardrum picks up "sound" and sends it to the middle ear.
2. Bones of middle ear:
- The ossicles are connected to each other and the first to the ear drum, the third to the oval window.
- Transmits sound waves to the oval window.
- Reducing the amplitude of the waves but increases the amplitude 20 times. The oval window helps in amplifying.
- Muscles atteched to the ossicles help protecting the ear from loud sounds.
3. The oval window:
- Transmits sound waves to the fluid filling the cochlea.
- The fluid is incompressible so second membranous window is needed: round window.
4. Hair cells in the cochlea:
- When the sound waves pass through the fluid in cochlea, the hair bundles vibrate.
- Each hair cell resonates in response to specific wavelengths of sound due to gradual gradations in width and thickness of cochlear membrane when hair bundles vibrate.
- Hair cells transmit action potentials across synapse with auditory nerve -->travel to auditory cortex in brain
That's the end of the blog regarding how sound is perceived by ear!
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4979856/525216_598486.png)
References:
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.pinterest.com%2Fpin%2F500040364850403667%2F&psig=AOvVaw3JdzDnl16hMGncd9TGSZOp&ust=1627290156689000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCLjfzrDu_fECFQAAAAAdAAAAABAJ
Drafted by Venetia (Biology)