Ears

Question 1

What are the THREE regions of the ear?

Answer 1

External, Middle & Inner.

Question 2

What does the External ear consist of?

Answer 2

Pinna, External auditory canal, Tympanic membrane.

Question 3

What does the Middle ear consist of?

Answer 3

THREE ossicles, Eustachian/Auditory tube, Oval & Round window.

Question 4

What does the Inner ear contain?

Answer 4

The Vestibule, The Cochlea, Semicircular canals.

Question 5

What is the function of the External ear?

Answer 5

-Pinna directs sound waves toward the Tympanic membrane,
-External auditory canal contains ceruminous glands which excrete cerumen to protect and lubricate the external ear.
-Tympanic membrane is vibrated by sound waves & transfers to the ossicles.

Question 6

What is the function of the Middle ear?

Answer 6

-The THREE ossicles transmit & amplify sound waves,
-Auditory tube leads to the Nasopharnx and assists to equalise pressure on both sides of the Tympanic membrane.

Question 7

What are the THREE ossicles?

Answer 7

Malleus, Incus, Stapes.

Question 8

What separates the External ear from the Middle ear?

Answer 8

The Tympanic membrane.

Question 9

What separates the Middle ear from the Inner ear?

Answer 9

The Oval & Round windows.

Question 10

What are the TWO main divisions of the Inner ear?

Answer 10

The Bony labyrinth & the Membranous labyrinth.

Question 11

What does the Bony labyrinth contain?

Answer 11

Perilymph & the Membranous labyrinth.

Question 12

What does the Membranous labyrinth contain?

Answer 12

Endolymph.

Question 13

What is the function of Perilymph & Endolymph?

Answer 13

Both liquids conduct sound & respond to mechanical forces during changes in the body position.

Question 14

What is the Cochlea?

Answer 14

A small snail shaped organ which contains receptors for hearing.

Question 15

What are the THREE channels of the Cochlea?

Answer 15

Scala Vestibuli,
Cochlea duct/Scala media,
Scala Tympani.

Question 16

Where the Scala vestibuli & the Scala tympani found? and what do they contain?

Answer 16

Both are located inside the Bony labyrinth and both contain Perilymph.

Question 17

Where is the Cochlea duct/Scala media found? and what does it contain?

Answer 17

Found in the Membranous labyrinth and contains Endolymph.

Question 18

What are the TWO membranes of the Cochlea duct?

Answer 18

Upper membrane: Vestibular membrane,
Lower membrane: Basilar membrane.

Question 19

What is found resting on the Basilar membrane?

Answer 19

A spiral organ known as the Organ of Corti - the organ of hearing.

Question 20

State the physiology of hearing in order- The process of hearing.

Answer 20

1- Sound waves vibrate the Tympanic membrane, vibration passes onto the Ossicles.
2- Vibration of Ossicles transfers & amplifies vibratory motion to the Oval window,
3- Pressure waves are created in the Perilymph of the Cochlea,
4- Pressure waves travel through Perilymph & pass through the Vestibular membrane into the Endolymph.
5- Pressure waves in the Endolymph cause the Basilar membrane to vibrate which moves the hair cells. This creates an action potential if the threshold is met.

Question 21

Which area of the Cochlea detects HIGH pitch sounds?

Answer 21

The base of the Cochlea.

Question 22

Which area of the Cochlea detects LOW pitch sounds?

Answer 22

The apex of the Cochlea.

Question 23

How is the volume of sound determined?

Answer 23

Loudness is determined by the intensity of sound waves.
Loud noises stimulate more hairs & generate more impulses.

Question 24

What is the function of the Vestibulocochlear nerve?

Answer 24

Carries impulses from the Vestibule & Organ of Corti.
Starts as two seperate branches- Vestibular & Cochlear.
Action potentials travel to the primary auditory area via the Cochlear branch of the Vestibulocochlear nerve.

Question 25

What is the definition of Equilibrium?

Answer 25

The state of being balanced & the position of the head in relation to the body.

Question 26

What is the receptor organ responsible for maintaining Equilibrium?

Answer 26

Vestibular apparatus.

Question 27

Where is the Vestibular apparatus located?

Answer 27

The Vestibule - saccule & utricle, Semicircular canals.

Question 28

What is meant by Static equilibrium?

Answer 28

Maintains positions of head relative to the force of gravity. Involves movement of tilt & acceleration/deceleration.

Question 29

What is meant by Dynamic equilibrium?

Answer 29

Maintenance of head position during sudden movement - rotation.

Question 30

What is the function of Semicircular canals?

Answer 30

Arranged at approximately right angles to eachother: to detects different movement. Thus giving. combined 3D sensitivity.

Question 31

What does the Semicircular duct contain?

Answer 31

Each duct has an Ampulla, each Ampulla has a Crista. Crista contains a group of hair cells that are equilibrium receptors. Each crista is covered by a Cupula.

Question 32

Explain the process of maintaining equilibrium while moving.

Answer 32

When you move, the semicircular ducts move with the body, however the endolymph moves at a different rate depending on force: gravity, acceleration. Movement of the Endolymph within Semicircular ducts moves the Crista contained within the Cupula. This moves the hair cells in the Cupula & if the threshold is met: an action potential is generated. This action potential than travels along the Vestibular branch of the Vestibulocochlear nerve to the Medulla Oblongata for interpretation.

Question 33

State ONE age related change to hearing.

Answer 33

Presbycusis: Progressive loss of hearing in both ears caused by damage and loss of hearing cells in the Spiral organ.