Chapter 17: Special Senses (Hearing)

Question 1

the ability to perceive sounds

Answer 1

HEARING

Question 2

the science that deals with the ears, nose,
pharynx (throat), and larynx (voice box)
and their disorders.

Answer 2

OTORHINOLARYNGOLOGY

Question 3

consists of the auricle, external auditory canal, and
eardrum

Answer 3

EXTERNAL EAR

Question 4

or pinna is a flap of elastic cartilage
shaped like the flared end of a trumpet and
covered by skin

Answer 4

 Auricle

Question 5

 The rim of the auricle

Answer 5

HELIX

Question 6

the inferior portion

Answer 6

LOBULE

Question 7

o is a curved tube about 2.5 cm (1 in.) long
that lies in the temporal bone and leads to
the eardrum.

Answer 7

 External Auditory Canal

Question 8

or eardrum is a thin, semitransparent
partition between the external auditory
canal and middle ear.

Answer 8

 Tympanic Membrane

Question 9

usually periodic ear irrigation or removal of wax with
a blunt instrument by trained medical personnel.

Answer 9

Impacted Cerumen

Question 10

a small, air-filled cavity in the petrous portion of the
temporal bone that is lined by epithelium

Answer 10

MIDDLE EAR

Question 11

attaches to the internal surface of the
tympanic membrane. The head of the
malleus articulates with the body of the
incus.

Answer 11

Malleus

Question 12

the middle bone in the series, articulates
with the head of the stapes

Answer 12

Incus

Question 13

o fits into the oval window.

Answer 13

 Stapes

Question 14

supplied by the mandibular branch of the
trigeminal (V) nerve, limits movement and
increases tension on the eardrum to
prevent damage to the inner ear from loud
noises

Answer 14

Tensor Tympani Muscle

Question 15

which is supplied by the facial (VII) nerve,
is the smallest skeletal muscle in the
human body.

Answer 15

Stapedius Muscle

Question 16

abnormally sensitive hearing due

Answer 16

Hyperacusia

Question 17

or pharyngotympanic tube, commonly
known as the eustachian tube.
o The auditory tube, which consists of both
bone and elastic cartilage, connects the
middle ear with the nasopharynx (superior
portion of the throat)

Answer 17

Auditory Tube

Question 18

also called the labyrinth because of its complicated
series of canals

Answer 18

INTERNAL EAR

Question 19

alternating high- and low-pressure regions
traveling in the same direction through
some medium (such as air)

Answer 19

Sound Waves

Question 20

The auricle directs sound waves into the external
auditory canal.
(2) When sound waves strike the tympanic membrane,
the alternating waves of high and low pressure in the
air cause the tympanic membrane to vibrate back
and forth. The tympanic membrane vibrates slowly in
response to low-frequency (low-pitched) sounds and
rapidly in response to high-frequency (high-pitched)
sounds.
(3) The central area of the tympanic membrane
connects to the malleus, which vibrates along with
the tympanic membrane. This vibration is transmitted
from the malleus to the incus and then to the stapes.
(4) As the stapes moves back and forth, its oval-shaped
footplate, which is attached via a ligament to the
circumference of the oval window, vibrates in the
oval window.
(5) The movement of the stapes at the oval window sets
up fluid pressure waves in the perilymph of the
cochlea. As the oval window bulges inward, it pushes
on the perilymph of the scala vestibuli.
(6) Pressure waves are transmitted from the scala
vestibuli to the scala tympani and eventually to the
round window, causing it to bulge outward into the
middle ear.
(7) As the pressure waves deform the walls of the scalea
vestibuli and scala tympani, they also push the
vestibular membrane back and forth, creating
pressure waves in the endolymph inside the cochlear
duct.
(8) The pressure waves in the endolymph cause the
basilar membrane to vibrate, which moves the hair
cells of the spiral organ against the tectorial
membrane. This leads to bending of the stereocilia
and ultimately to the generation of nerve impulses in
first-order neurons in cochlear nerve fibers.

Answer 20

PHYSIOLOGY OF HEARING

Question 21

The axons of these neurons form the
cochlear branch of the vestibulocochlear
(VIII) nerve
o These axons synapse with neurons in the
cochlear nuclei in the medulla oblongata.

Answer 21

COCHLEAR NUCLEI

Question 22

Some of the axons from the cochlear nuclei
decussate (cross over) in the medulla,
ascend in a tract called the ___________ on the opposite side

Answer 22

lateral
lemniscus

Question 23

terminate in the inferior colliculus of the
midbrain

Answer 23

 Inferior Colliculus

Question 24

Other axons from the cochlear nuclei end in
the ____________ of the pons.

Answer 24

superior olivary nucleus

Question 25

From each inferior colliculus, axons extend to the medical geniculate nucleus of the thalamus

Answer 25

Medial Geniculate nucleus

Question 26

Neurons in the thalamus, in turn, project axons to the ________________ of the cerebral cortex in the temporal lobe of the cerebrum ) in the temporal lobe, where conscious awareness of sound occurs

Answer 26

primary auditory area

Question 27

The ear not only detects sound, but also changes in equilibrium or balance.  Body movements that stimulate the receptors for equilibrium include linear acceleration or deceleration, such as when a car suddenly takes off or stops; tilting the head forward or backward, as if to say “yes”; and rotational (angular) acceleration or deceleration, such as when a rollercoaster takes a quick curve

Answer 27

EQUILIBRIUM

Question 28

Attached to the inner walls of both the utricle and the saccule is a small, thickened region

Answer 28

Mascula

Question 29

Two types of cells

Answer 29

Hair Cells (sensory receptor)  Supporting Cells

Question 30

As in the cochlea, the stereocilia are connected by tip links. Collectively, the stereocilia and kinocilium

Answer 30

 Hair bundle

Question 31

Scattered among the hair cells are columnar supporting cells that probably secrete the thick, gelatinous, glycoprotein layer

Answer 31

Otolithic membrane

Question 32

A layer of dense calcium carbonate crystals o extends over the entire surface of the otolithic membrane.

Answer 32

Otoliths

Question 33

The three semicircular ducts lie at right angles to one another in three planes posterior semicircular ducts, and the horizontal one is the lateral semicircular duct

Answer 33

SEMICIRCULAR DUCTS

Question 34

The dilated portion of each duct o contains a small elevation called the crista

Answer 34

Ampulla

Question 35

Each crista consists of a group of hair cells and supporting cells

Answer 35

 Crista

Question 36

The hair cells contain a kinocilium and stereocilia (collectively known as a hair bundle), and the stereocilia are interconnected via tip links

Answer 36

Hair Cells

Question 37

Covering the crista is a mass of gelatinous material

Answer 37

Cupula

Question 38

Covering the crista is a mass of gelatinous material

Answer 38

Cupula