Exam 3: Ear Flashcards Preview

Anatomy A-215 > Exam 3: Ear > Flashcards

Flashcards in Exam 3: Ear Deck (33):
1

Hearing (Audition)

-detecting sound waves and converting them into nerve impulses

2

Equilibrium (Balance)

-detect position of head

3

External Ear

-consists of auricle, external acoustic meatus and tympanic membrane

4

Auricle (Pinna)

-outer mass of tissue
-function: collects sound waves to external acoustic meatus

5

External Acoustic Meatus

-between auricle and tympanic membrane
-function: directs sound to tympanic membrane

6

Tympanic Membrane (Eardrum)

-function: move/vibrate auditory ossicles when sound waves vibrate membrane

7

Middle Ear

-lateral (external) boundary is tympanic membrane
-medial (internal) boundary is oval window and round window
-contains auditory ossicles (ear bones)
and auditory tube

8

Auditory Ossicles

-malleus (hammer), incus (anvil), stapes (stirrup)
-connects with oval window of inner ear (where sound waves are transmitted to inner ear)
-Function: transmit and amplify sound waves to inner ear

9

Auditory Tube

-connects middle ear with nasopharynx (upper throat
-function: equalizes pressure in middle ear

10

Popping sensation when changing altitudes

-Caused by auditory tube opening and releasing pressure

11

Inner Ear

-consists of bony labyrinth and membranous labyrinth

12

Bony Labyrinth

-spaces/cavities inside temporal bone
-consists of vestibule, semicircular canals, and cochlea

13

Membranous Labyrinth

-membranous sacs/tubes that rest inside the bony labyrinth
-consists of utricle, saccule, semicirular ducts, and cochlear duct (scala media)

14

Perilymph

-fluid between bony and membranous labyrinth
-similar to CSF (in composition and function)

15

Endolymph

-fluid inside membranous labyrinth
-different chemically from perilymph
-helps conduct sound waves

16

Vestibule

-oval central portion of bony labyrinth

17

Semicircular Canals

-three circular spaces/canals in bony labyrinth

18

Cochlea

-spiral chamber of bony labyrinth

19

Utricle

-sac inside vestibule
-membranous labyrinth
-involved in interpreting equilibrium

20

Saccule

-another sac inside vestibule
-membranous labyrinth
-involved in interpreting equilibrium

21

Semicircular Ducts

-three membranous tubes in semicircular canals
-membranous labyrinth
-involved in interpreting equilibrium

22

Cochlear Duct (Scala Media)

-membranous tube inside cochlea
-membranous labyrinth
-involved in hearing
-splits cochlea into two chambers

23

How is equilibrium information transmitted?

-through vestibular branch of vestibulocochlear nerve CN VIII

24

Scala Vestibuli

-above cochlear duct
-filled with perilymph
-part of cochlea (bony labyrinth)
-connects to oval window

25

Oval Window

-directs sound waves through scala vestibuli

26

Scala Tympani

-below cochlear duct
-filled with perilymph
-part of cochlea (bony labyrinth)
-connects to round window

27

Round Window

-excess sound waves leave inner ear through this

28

Spiral Organ (Organ of Corti)

-filled with endolymph
-contained in cochlear duct
-rests on basilar membrane
-contains hair cells with have stereocilla (touch tectorial membrane)

29

How sound waves travel

-when sound waves enter via the scala vestibuli, they vibrate a small portion of the basilar memrane
-when the basilar membrane moves the stereocilia of the hair cells touch the tectorial membrane
-bending of the stereocilia generates a nerve impulse
-nerve impulses are sent to the brain via the cochlear brance of the vestibulocochlear nerve CN VIII
-remaining sound waves are transferred to the scala tympani and exit the inner ear via the round window

30

Complete (Brief) Overview of Hearing

-Sound waves are collected by auricle, travel in external acoustic meatus, sent to tympanic membrane
-Vibration of tympanic membrane causes vibration of auditory ossicles, wich in turn vibrates the oval window
-Sound waves travel through the scala vestibuli and vibrates a portion of the basilar membrane (which is attached to spiral organ)
-Stereocilia of the hair cells bend against the tectorial membrane which generates a nerve impulse
-Nerve impulse is sent to the brain via the vestibulocochlear nerve CN VIII
-remaining sound waves are transferred to the scala tympani and leave the inner ear through the round window

31

Otitis Media

-inflammation of middle ear
-may occur after respiratory infection
-spreads to auditory tube
-pain and pressure in middle ear
-can rupture tympanic membrane

32

Myringotomy

-surgical procedure to to put in tubes in tympanic membrane
-for chronic ear infections
-help drain fluid in middle ear

33

Frequencies and Basilar Membrane

-low notes (frequencies) vibrate basilar membrane far away from oval window
-high notes (frequencies) vibrate basilar membrane close to oval window