Special Sense (Ear)

Question 1

What are the 3 anatomical regions of the ear?

Answer 1

external ear
middle ear (tympanic cavity)
inner ear (labyrinth)

Question 2

What are the external and middle ears mainly involved in?

Answer 2

reception and transmission of sound waves to inner ear, where sound waves are converted to electrical impulses and conveyed to brain

Question 3

What does the inner ear contain?

Answer 3

organ of balance

Question 4

External Ear

What does the external ear include? (2)

Answer 4

• auricle

- external acoustic meatus

Question 5

External Ear

What is the auricle?

Answer 5

has cartilaginous core covered by thin skin

Question 6

External Ear

What does the auricle carry?

Answer 6

some contours that collect sound and transfer it to external acoustic meatus

Question 7

External Ear

What is the lobule?

Answer 7

inferior part of auricle, and its cartilage is replaced by connective tissue

Question 8

External Ear

What is the external acoustic meatus?

Answer 8

S-shaped long canal extending from auricle to tympanic membrane (ear drum)

Question 9

External Ear

Is the external acoustic meatus bony or cartilaginous?

Answer 9

lateral ⅓ is cartilaginous

medial ⅔ is bony

Question 10

External Ear

What does the thin skin covering the external acoustic meatus contain?

Answer 10

ceruminous glands (modified sweat glands) that secrete cerumen (ear wax) that slows growth of microorganisms in external acoustic meatus, and reduces risk of infection

Question 11

Middle Ear (Tympanic Cavity)

What is the middle ear?

Answer 11

irregular cubic space contained within petrous part of temporal bone

Question 12

Middle Ear (Tympanic Cavity)

What is the middle ear lined by?

Answer 12

mucous membrane that is continuous with that of nasopharynx

Question 13

Middle Ear (Tympanic Cavity)

What are the 3 ossicles?

Answer 13

malleus, incus, and stapes

Question 14

Middle Ear (Tympanic Cavity)

What do the 3 ossicles do?

Answer 14

amplify and convey sound from tympanic membrane to inner ear

Question 15

Middle Ear (Tympanic Cavity)

How are ossicles jointed to each other?

Answer 15

by synovial joints

Question 16

Middle Ear (Tympanic Cavity)

What are the 2 small skeletal muscles in the middle ear?

What do they do?

Answer 16

tensor tympani and stapedius

dampen sound

Question 17

Middle Ear (Tympanic Cavity)

What are the 4 walls of the tympanic cavity with more distinct features?

Answer 17

lateral wall
medial wall
anterior wall
superior wall

Question 18

Middle Ear (Tympanic Cavity)

What does the lateral wall carry?

Answer 18

tympanic membrane separating middle and external ears

Question 19

Middle Ear (Tympanic Cavity)

What is the medial wall?

Answer 19

thin bony plate that separates tympanic cavity from inner ear

Question 20

Middle Ear (Tympanic Cavity)

What does the medial wall carry?

Answer 20

2 openings

• fenestra vestibuli (oval window) covered by stapes
• fenestra cochlea (round window) covered by membrane

Question 21

Middle Ear (Tympanic Cavity)

What is the anterior wall connected to?

Answer 21

nasopharynx via auditory tube

Question 22

Middle Ear (Tympanic Cavity)

What is the superior wall?

Answer 22

(roof) separates tympanic cavity from middle cranial fossa

Question 23

Inner Ear (Labyrinth)

Where is the inner ear?

Answer 23

housed within petrous part of temporal bone

Question 24

Inner Ear (Labyrinth)

What are the 2 divisions of the inner ear?

Answer 24

osseous and membranous divisions

• bony labyrinth
• membranous labyrinth

Question 25

Inner Ear (Labyrinth) What is the bony labyrinth?

Answer 25

series of boney cavities divided into semicircular canals, vestibule, and cochlea

Question 26

Inner Ear (Labyrinth) What does the bony labyrinth contain?

Answer 26

perilymph - fluid similar to CSF that surrounds enclosed membranous labyrinth

Question 27

Inner Ear (Labyrinth) - Bony Labyrinth What are semicircular canals?

Answer 27

3 tubes that open into vestibule

Question 28

Inner Ear (Labyrinth) - Bony Labyrinth What is the vestibule?

Answer 28

connected to middle ear (via oval window) and cochlea

Question 29

Inner Ear (Labyrinth) - Bony Labyrinth What is the cochlea?

Answer 29

shell-shaped part of bony labyrinth

Question 30

Inner Ear (Labyrinth) - Bony Labyrinth How is the cochlea divided?

Answer 30

lumen of this tube is partially divided into two sections by bony septum (lamina) - scala vestibuli - scala tympani

Question 31

Inner Ear (Labyrinth) - Bony Labyrinth Where is the scala vestibuli?

Answer 31

located in upper section of lumen that ends to fenestra vestibuli (oval window)

Question 32

Inner Ear (Labyrinth) - Bony Labyrinth Where is the scala tympani?

Answer 32

located in lower section of lumen that ends to fenestra cochlea (round window)

Question 33

Inner Ear (Labyrinth) - Membranous Labyrinth Where is the membranous labyrinth?

Answer 33

suspended in bony labyrinth

Question 34

Inner Ear (Labyrinth) - Membranous Labyrinth What is the membranous labyrinth formed by?

Answer 34

series of membranous sacs and ducts

Question 35

Inner Ear (Labyrinth) - Membranous Labyrinth What is the membranous labyrinth filled with? What is it surrounded with?

Answer 35

filled with endolymph surrounded by perilymph

Question 36

Inner Ear (Labyrinth) - Membranous Labyrinth What does the membranous labyrinth include? (4)

Answer 36

- membranous semicircular ducts - utricle - saccule - cochlear duct

Question 37

Inner Ear (Labyrinth) - Membranous Labyrinth Where are the membranous semicircular ducts?

Answer 37

located within bony semicircular canal, and open to utricle

Question 38

Inner Ear (Labyrinth) - Membranous Labyrinth What is the ampula?

Answer 38

dilated part of membranous semicircular duct that contains crista that carries equilibrium receptors

Question 39

Inner Ear (Labyrinth) - Membranous Labyrinth Where are the utricle and saccule?

Answer 39

inside vestibule, and are connected to each other by a duct saccule is also connected to cochlear duct

Question 40

Inner Ear (Labyrinth) - Membranous Labyrinth What is the macula?

Answer 40

elevation in saccule that carries equilibrium receptors

Question 41

Inner Ear (Labyrinth) - Membranous Labyrinth What is the vestibular nerve?

Answer 41

arises from crista and macula

Question 42

Inner Ear (Labyrinth) - Membranous Labyrinth What does the cochlear duct carry?

Answer 42

organ of corti (organ of hearing) that gives rise to cochlear nerve