Ears System

Question 1

Three Parts of Ears

Answer 1

1. External ear- from auricle ( pinna) to tympanic membrane
2. Middle ear- from malleus to bony labyrinth
3. Inner ear- from bony labyrinth inward

Question 2

Important Landmarks of Visible part of ear (pinna/ auricle)

5

Answer 2

Helix- Rim

Lobule- Inferior portion

External auditory meatus- opening into the ear canal

Tragus- pointed eminence

Mastoid process- projection from mastoid portion of temporal bone

Question 3

External Auditory Canal

Function, length and lined with?

Answer 3

Function: funnels sound waves into the ear

Length: 2.5-3 cm long

Lined with cerumen

Question 4

Tympanic Membrane (ear drum)

Function

Answer 4

• Function: Receives sound waves as vibrations & transmits them to the auditory ossicles of the middle ear

Question 5

Middle Ear

Auditory Ossicles (Bones)

Functions and 3 bones

Answer 5

Function: conducts vibrations from the tympanic membrane to the inner ear

3 bones: Malleus(hammer), incus(anvil), stapes(stirrup)

Question 6

Middle Ear

Eustachian Tube

Function

Answer 6

Connects middle ear with nasopharynx and allows passage of air. Stabilizes pressure in the middle ear.

Question 7

Middle Ear

3 Primary Functions

Answer 7

1. Conducts sound vibrations from outer ear to central hearing apparatus of middle ear
2. Protects the inner ear by reducing the amplitude of sounds (2 small skeletal muscles to dampen noises)
3. Eustachian tube allows equalization of air pressure on each side of the tympanic membrane

Question 8

Inner Ear

What is the Bony labyrinth

What does the Vestibular Apparatus consist of and what is the function

What is the function of the cochlea

Answer 8

Bony labyrinth- holds the sensory organs for hearing & equilibrium

Vestibular apparatus

• Vestibule & Semicircular canals
• Function: Equilibrium and balance

Cochlea
Function: Hearing

Question 9

What is the pathway of Hearing

3 steps

Answer 9

Sound waves enter the ear via external auditory canal

1. Waves strike the tympanic (eardrum) membrane , which causes the malleus, incus, and stapes to vibrate
2. Vibrations enter the cochlea – the movements of the stapes cause the basilar membrane to vibrate at the frequency of the sound
3. The vibrations bend the hair cells in the Organ of Corti and convert to electrical impulses –these travel to the brain (via cranial nerve VIII) and are interpreted as sound

Question 10

What are the three type of Hearing Loss and what are the causes

Answer 10

Conductive

• Mechanical dysfunction due to an interruption in the conduction of sounds waves through the ear to the ear drum
• Partial hearing loss
• Causes: damage to external and/or middle ear

Sensorineural

• Nervous system damage beyond the outer/middle ear (perceptive loss)
• Presbycusis- gradual nerve degeneration
• Causes: disease of the inner ear, CN VIII, or auditory area in cerebral cortex

Mixed – combo of conductive and sensorineural

Question 11

How is equilibrium achieved

What does inflammation of the ear do

Vertigo

Answer 11

• The labyrinth determines your position in space
• Registers the position of the head
• Inflammation of the ear= wrong information to the brain
• Vertigo- strong spinning, whirling sensation