Class #10

Question 1

What are the three regions of the ear?

Answer 1

External, middle, internal ear

Question 2

What is the primary function of the external ear?

Answer 2

Sound localization (determining direction and distance of sound).

Question 3

What are the three main structures of the external ear?

Answer 3

External auditory canal (meatus)

Pinna (auricle)

Tympanic membrane (eardrum)

Question 4

What type of cartilage forms the pinna?

Answer 4

Elastic cartilage covered by skin

Question 5

What glands produce earwax?

Answer 5

Ceruminous glands

Question 6

What is the function of cerumen (earwax)?

Answer 6

Protects and lubricates external auditory canal
+ traps debris.

Question 7

What structure vibrates in response to sound waves?

Answer 7

Tympanic membrane (eardrum).

Question 8

What is the helix?

Answer 8

The outer rim of the auricle of ear

Question 9

What structure lies parallel to the helix on the auricle?

Answer 9

Antihelix.

Question 10

What is the lobule?

Answer 10

The inferior soft portion of the ear (earlobe).

Question 11

What is the concha?

Answer 11

The deep cavity leading to the external auditory canal.

Question 12

Where is the middle ear located?

Answer 12

In the petrous portion of the temporal bone

Question 13

What fills the middle ear cavity?

Answer 13

Air

Question 14

What are the two openings on the medial wall of the middle ear?

Answer 14

Oval + Round window.

Question 15

What structure connects the middle ear to the pharynx?

Answer 15

Eustachian (pharyngotympanic) tube.

Question 16

What is the function of the pharyngotympanic tube?

Answer 16

Equalizes air pressure between the middle ear and atmosphere.

Question 17

What action opens the pharyngotympanic tube?

Answer 17

Swallowing or yawning.

Question 18

What are the three auditory ossicles?

Answer 18

Malleus, Incus, and Stapes

Question 19

Which ossicle attaches to the tympanic membrane?

Answer 19

Malleus

Question 20

Which ossicle attaches to the oval window?

Answer 20

Stapes.

Question 21

What is the main function of the ossicles?

Answer 21

Amplify sound vibrations (~20×).

Question 22

What muscle attaches to the malleus?

Answer 22

Tensor tympani

Question 23

What nerve innervates tensor tympani?

Answer 23

Trigeminal nerve (CN V3).

Question 24

What muscle attaches to the stapes?

Answer 24

Stapedius.

Question 25

What nerve innervates stapedius?

Answer 25

Facial nerve (CN VII).

Question 26

What condition results from stapedius paralysis?

Answer 26

Hyperacusis (abnormally sensitive hearing).

Question 27

What are the three parts of the bony labyrinth? (inner ear)

Answer 27

Vestibule Semicircular canals Cochlea

Question 28

What fluid fills the bony labyrinth? (inner ear)

Answer 28

Perilymph.

Question 29

What fluid fills the membranous labyrinth? (inner ear)

Answer 29

Endolymph

Question 30

What shape is the cochlea?

Answer 30

Snail-shaped, ~2.5 turns.

Question 31

What are the three compartments of the cochlea?

Answer 31

Scala vestibuli , Scala media (cochlear duct), and Scala tympani.

Question 32

Which compartment contains the cochlear duct?

Answer 32

Scala media.

Question 33

Which compartment is connected to the oval window? (cochlea)

Answer 33

Scala vestibuli.

Question 34

Which compartment ends at the round window? (cochlea)

Answer 34

Scala tympani.

Question 35

What structure connects the scala vestibuli and scala tympani? (cochlea)

Answer 35

Helicotrema.

Question 36

What membrane supports the organ of Corti?

Answer 36

Basilar membrane.

Question 37

What is the function of the organ of Corti?

Answer 37

It is the sensory organ of hearing.

Question 38

What cells detect sound vibrations? (organ of corti)

Answer 38

Hair cells.

Question 39

What is the sequence of sound conduction through the ear?

Answer 39

Sound waves → tympanic membrane → ossicles → oval window → cochlea → hair cells → auditory nerve.

Question 40

What happens when hair cells bend?

Answer 40

Mechanically gated channels open → receptor potential → action potentials in auditory nerve.

Question 41

What ion enters hair cells during stimulation?

Answer 41

Potassium (K⁺)

Question 42

What ion triggers neurotransmitter release from hair cells?

Answer 42

Calcium (Ca²⁺).

Question 43

What happens when stereocilia bend toward the tallest stereocilium?

Answer 43

Depolarization and increased nerve firing

Question 44

What happens when stereocilia bend away from the tallest stereocilium?

Answer 44

Hyperpolarization and reduced nerve firing.

Question 45

Where are auditory neuron cell bodies located?

Answer 45

Spiral ganglion.

Question 46

Which cranial nerve carries hearing information?

Answer 46

Vestibulocochlear nerve (CN VIII).

Question 47

Where does the auditory pathway terminate?

Answer 47

Primary auditory cortex in the temporal lobe.

Question 48

What are the two major types of deafness?

Answer 48

Conduction deafness, Nerve deafness.

Question 49

What causes conduction deafness?

Answer 49

Mechanical blockage preventing sound reaching the inner ear.

Question 50

What causes nerve deafness?

Answer 50

Damage to cochlear hair cells.

Question 51

What is the purpose of a cochlear implant?

Answer 51

Convert sound waves into electrical signals for the brain.

Question 52

What type of deafness do cochlear implants treat?

Answer 52

Nerve deafness due to hair cell damage

Question 53

What does the vestibular apparatus detect?

Answer 53

Body position and head movement (equilibrium).

Question 54

What two structures form the vestibule?

Answer 54

Utricle and saccule.

Question 55

What receptors detect gravitational equilibrium?

Answer 55

Macula (otolith organs)

Question 56

What are otoliths?

Answer 56

Calcium carbonate crystals that add weight to the otolithic membrane.

Question 57

What type of equilibrium do semicircular canals detect?

Answer 57

Rotational (dynamic) equilibrium.

Question 58

What structure contains hair cells in semicircular canals?

Answer 58

Crista ampullaris

Question 59

What gelatinous structure surrounds hair cells in semicircular canals?

Answer 59

Cupula.

Question 60

What is vertigo?

Answer 60

Sensation of dizziness and spinning due to vestibular disturbance.

Question 61

What causes motion sickness?

Answer 61

Conflict between vestibular and visual sensory input

Question 62

What is presbycusis?

Answer 62

Age-related hearing loss due to degeneration of the organ of Corti.

Question 63

Which structure equalizes air pressure in the middle ear?

Answer 63

Pharyngotympanic (Eustachian) tube.

Question 64

Where is the organ of Corti located?

Answer 64

Scala media.

Question 65

What type of receptors are found in the semicircular canals, utricle, and saccule?

Answer 65

Mechanoreceptors.

Question 66

The inner wall of the optic cup develops into what structure?

Answer 66

Neural layer of the retina.

Question 67

Otosclerosis

Answer 67

Overgrowth of bone that causes the stapes to adhere to the oval window Most frequent cause of conduction deafness in adults

Question 68

QUIZ: What structure allows air pressure to equalize in the middle ear?

Answer 68

pharyngotympanic tube

Question 69

QUIZ: The organ of Corti (organ of hearing) is present in which region?

Answer 69

Cochlear duct

Question 70

QUIZ: Which structure forms the main receptor for sound?

Answer 70

Inner hair cells

Question 71

QUIZ: Where can we find the otolith organs that detect the gravitational (static) equilibrium?

Answer 71

Utricle and saccule

Question 72

QUIZ: The inner wall of the optic cup develops into which structure?

Answer 72

The neural layer of the retina

Question 73

QUIZ: TRUE/FALSE The membranous labyrinth consists of membranes inside the bony labyrinth which are filled with endolymph.

Answer 73

TRUE

Question 74

QUIZ: T/F Sound transduction includes converting mechanical vibrations into electrical signals.

Answer 74

TRUE

Question 75

QUIZ: T/F A cochlear implant is a device that translates sounds into electrical signals that can be interpreted by the brain.

Answer 75

TRUE

Question 76

QUIZ: T/F The receptors found in the semicircular canals, utricle, and saccule are chemoreceptors.

Answer 76

FALSE

Question 77

QUIZ: T/F The ectoderm of the lateral walls of the prosencephalon (forebrain) enlarges and grows toward the surface ectoderm to form the optic vesicles.

Answer 77

TRUE