Chapter 14, Lesson 4

Guided Reading Activity 53

Ears and Hearing Protection

1. What are the three main sections of the ear?

The outer ear

The middle ear

The inner ear

2a. List the function of each part of the outer ear:

• Auricle: Helps channel sound waves into the external auditory canal.

Auricle--------

2b. List the function of each part of the outer ear:

• External auditory canal: Leads to the eardrum.

External auditory canal------------------------------

2c. List the function of each part of the outer ear:

• Hairs and wax: Protects the ear from dust and foreign objects.

2d. List the function of each part of the outer ear:

• Tympanic Membrane: a barrier between the outer ear and the middle ear.

Tympanic Membrane:

3a. Answer the following about the middle ear:

• What are the auditory ossicles?– Thee small

bones linked together that connect the eardrum to the inner ear.

Incus or Anvil-------------------------

Stapes or Stirrup----------------

Malleous or Hammer-------------------------

3b. Answer the following about the middle ear:

• What does the eustachian tube do?– Connects the middle

ear to the throat.– Allows pressure to

be equalized on either side of the eardrum when you swallow or yawn.

eustachian tube------------------

4a. Answer the following questions about the inner ear.

• The Labyrinth.– Also called the

inner ear.– A network of

curved spiral passages.

4b. Answer the following questions about the inner ear.

• Describe the shape and function of the cochlea.– Spiral-shaped canal– The area of hearing in

the inner ear where balance is controlled.

Cochlea------------------------

5. Describe how hearing occurs.

• Sound waves enter the external auditory canal and cause the eardrum to vibrate

• Vibrations cause fluid in the cochlea to move

• This stimulates receptor cells to send a nerve impulse to the brain.

• The brain interprets the sound.

6. Describe how your ears help you maintain your balance.

• Tiny hairs located in the crista sense movement and send nerve impulses to the brain.

• The brain then signals muscles to make adjustments to maintain balance.

Crista-------------------------Semicircular canals

7. List four ways to help keep your ears healthy.

• Clean them regularly.• Protect the outer ear from injury and extreme

cold.• Wear protective gear such as batting helmets

when playing sports.• Wear a hat that covers both the auricles and

the earlobes in cold weather.• Keep foreign objects out of the ear.• Have ear infections treated immediately.• Avoid loud noise.

8. Name the two categories of hearing loss.

• Conductive

• Sensorineural

9. Conductive hearing loss.

• What is it?– Sound waves are not passed from the

outer to the inner ear.

• What is the most common cause of hearing difficulties in children?– The build up of fluid within the middle ear,

often due to infection.

10. Sensorineural hearing loss.

• Causes– Damage to the cochlea, the auditory nerve or the

brain.

• What is tinnitus?– Ringing, buzzing, whistling, roaring, hissing, or

other sound is heard in the ear in the absence of external sound.

• What are the causes of tinnitus?– Natural aging– High blood pressure– Overexposure to loud noise.

11. List three steps to protect your ears from tinnitus.

• Lower the volume of the source of the noise.

• Wear earplugs in noisy environments.• Limit the length of time you are exposed to

loud noise.