Physics of the Ear and Hearing

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Questions and Answers

What is the primary function of the pinna?

To decode and analyze electrical nerve signals

To amplify sound

To protect the eardrum from shocks

To direct sound waves towards the tympanic membrane (correct)

What is the length of the auditory canal?

1.5 cm

3.5 cm

2.5 cm (correct)

4.5 cm

What is the function of the auditory canal?

To decode and analyze electrical nerve signals

To amplify sound by acting as a resonator (correct)

To convert mechanical pulses into electrical signals

To transmit sound waves to the inner ear

What is the role of the middle ear?

To transmit sound waves to the inner ear Signup and view all the answers

What is the function of the inner ear?

To convert mechanical pulses into electrical signals Signup and view all the answers

How does the auditory system work?

It amplifies sound waves and converts them into electrical signals Signup and view all the answers

What is the role of the outer ear?

To collect and direct sound waves towards the tympanic membrane Signup and view all the answers

What is the function of the tympanic membrane?

To transmit sound waves to the middle ear Signup and view all the answers

What is the purpose of the auditory cortex?

To decode and analyze electrical nerve signals Signup and view all the answers

What is the primary function of the ear?

To receive sound waves and aid in balance and body position Signup and view all the answers

What is the velocity of sound in air?

330 m/s Signup and view all the answers

What is the frequency of sound wave that enhances the sensitivity of the ear?

2000-4000 Hz Signup and view all the answers

What is the main function of the tympanic membrane?

To transfer sound waves into the ossicles of the middle ear Signup and view all the answers

What happens to the acoustical signal when it hits the eardrum?

It is partially reflected and partially transmitted Signup and view all the answers

What is the ratio of the force on the oval window to the force on the eardrum?

1.5:1 Signup and view all the answers

What is the area of the oval window compared to the area of the eardrum?

Smaller Signup and view all the answers

What is the function of the middle ear bones?

To act as a lever system to amplify pressure on the oval window Signup and view all the answers

Why is most of the incoming wave intensity lost for the hearing process?

Due to impedance mismatch at the eardrum Signup and view all the answers

What is the frequency range in which the ear is most sensitive?

2000-4000 Hz Signup and view all the answers

What is the role of the tympanic membrane in sound wave transmission?

To transfer sound waves into the ossicles of the middle ear Signup and view all the answers

What is the primary function of the inner ear?

To transform the energy of compressional waves into nerve impulses Signup and view all the answers

What structure connects the cochlea to the middle ear?

Stirrup (or stapes) Signup and view all the answers

What is the purpose of the basilar membrane?

To separate the scala media from the scala tympani Signup and view all the answers

What type of sensory cells are found along the basilar membrane?

Inner and outer hair cells Signup and view all the answers

What happens when sound energy is transmitted to the cochlea?

The basilar membrane vibrates up and down Signup and view all the answers

What is the result of the hair cells shearing on the tectorial membrane?

Electrical charges are generated in the hair cells Signup and view all the answers

Where do high frequency sounds produce the greatest motion of the basilar membrane?

Near the oval window Signup and view all the answers

What is the purpose of the Reissner membrane?

To separate the scala vestibule from the scala media Signup and view all the answers

What does the cochlea resemble in shape?

A snail Signup and view all the answers

What type of testing is represented by the symbol 'O' in the figure?

Air conduction testing Signup and view all the answers

Study Notes

Hearing System

The ear is the organ that detects sound and aids in balance and body position.
It consists of three parts: outer, middle, and inner ears.
The ear is a converter of weak mechanical waves in air into electrical pulses in the auditory nerve.

Parts of the Ear

Outer Ear:
- Collects and directs sound waves towards the tympanic membrane.
- Consists of pinna, auditory canal, and tympanic membrane.
- Pinna:
  - Collects sound, acting as a funnel to amplify sound and directing sound toward the ear canal.
  - Protects the eardrum from shocks and prevents harmful items from entering the ear canal.
- Auditory canal:
  - A tube running from the outer ear to the middle ear.
  - Functions:
    - Protects the ear from excessive vibrations.
    - Amplifies sound by acting as a resonator.
Middle Ear:
- Transfers sound from the outer ear to the inner ear.
- Consists of hammer, anvil, and stirrup.
- Functions:
  - Acts as a lever system to amplify the pressure on the oval window.
  - Filter out noise generated in the body.
Inner Ear:
- Transforms the energy of compressional waves into nerve impulses.
- Consists of:
  - Cochlea: a snail-shaped structure that converts sound waves into electrical signals.
  - Vestibular chamber, middle chamber, and tympanic chamber.
  - Basilar membrane: separates the scala media from the scala tympani.
  - Hair cells: respond to the frequency of sound waves.
- Functions:
  - High frequency sounds produce the greatest motion of the basilar membrane near the oval window.
  - Low frequency sounds produce the greatest motion of the basilar membrane farthest from the apex.
  - Different nerve cells produce electrical pulses depending on the frequency of sound waves.

Hearing Loss (Deafness)

Not covered in this lecture.

Hearing Test (Audiometer)

Not covered in this lecture.

Additional Notes

The velocity of sound in air is 330 m/s.
The resonance of the ear canal enhances the sensitivity of the ear in the higher frequency range (2000-10000 Hz).
The best sensitivity of the ear is in the region 2000-4000 Hz.
Reflection and transmission of acoustical signals at the tympanic membrane occur due to impedance mismatch.
The middle ear bones act as a lever system to amplify the pressure on the oval window.

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Description

This quiz covers the anatomy and physiology of the hearing system, including the structure of the ear and types of hearing loss. Topics include the outer, middle, and inner ear, as well as hearing tests and deafness.