Special Senses of The Ear

Question 1

Functions of the ear (2)

Answer 1

enables the sense of hearing

provides a sense of equilibrium

Question 2

Anatomy of the ear

-Outer (External) Ear: contains? (3)

Answer 2

Auricle or Pinna
External Auditory Canal (Meatus)
Tympanic membrane (eardrum)

Question 3

Auricle or Pinna

location? function? contains?

Answer 3

(cuff hand to hear better) (Mikey Mouse has big auricles)
exterior ear structure
collects sound waves
Lobule- ear lobe

Question 4

External Auditory Canal (Meatus)

size? location? function? contains?

Answer 4

(where you put q-tip)
2.5 cm opening into temporal bone
directs soundwaves to eardrum
contains specialized sweat glands
   -Ceruminous glands: secrete cerumen (earwax)

Question 5

Tympanic membrane (eardrum)
description?
function?

Answer 5

semi-transparent membrane

sound waves cause it to vibrate & causes ossicles to vibrate

Question 6

Anatomy of the ear

Middle Ear: contains? (4)

Answer 6

Auditory ossicles
Round window
Oval window 
auditory tube (eustachian tube)

Question 7

Auditory ossicles

Answer 7

transmit & amplify vibrations from tympanic membrane to oval window
smallest bones, attached by ligaments across middle ear
-Malleus (hammer): attached to tympanic membrane
-Incus (anvil)
-Stapes (stirrup): ‘stirrup’ fits into oval window

Question 8

Round window

Answer 8

below oval window
involved in air pressure regulation
(opening mouth, hear pop bc pressure builds in plane)

Question 9

oval window

Answer 9

opening in wall of middle ear

stapes connected by ligaments to window

Question 10

Auditory tube (eustachian tube)
functions? contains? location?

Answer 10

connects middle ear to throat through ROUND window
bone & elastic cartilage
allow air to enter & leave middle ear
-equalizes internal air pressure w/ atmospheric pressure

Question 11

Anatomy of the ear
-Inner (internal) Ear: divisions? (2)
aka?

Answer 11

aka labyrinth (series of canals)
2 Divisions:
Osseous (Bony) Labyrinth
Membraneous Labyrinth

Question 12

Osseous (Bony) Labyrinth

filled with? location?

Answer 12

encloses the inner layer - membraneous labyrinth
filled w/ PERILYMPH
-similar to spinal fluid

Question 13

What are the 3 layers the Osseous (Bony) Labyrinth is divided into?

Answer 13

1) Vestibule (semicircular canals & cochlea go into this)
2) Semicircular canals (equilibrium)
3) Cochlea (hearing, snail)

Question 14

Membraneous Labyrinth

description? contains? filled with?

Answer 14

series of sacs & tubes inside bony labyrinth
contains hearing & equilibrium receptors
filled w/ endolymph
-filled w/ Na+ & K+ ions for generation of auditory impulses in brain

Question 15

Vestibule

description? location? contains? function?

Answer 15

(chamber)
Oval, central portion of bony labyrinth
inside is membraneous labyrinth that consists of 2 sacs: Utricle & Saccule
-contain macula
-hair cells for static equilibrium (body position)
generates nerve impulses to vestibulocochlear nerve 8

Question 16

Semicircular Canals

description? location? contain?

Answer 16

anterior & posterior vertical canals
lateral horizontal canal
end of each canal enlargement called ampulla
contain receptors for equilibrium

Question 17

Semicircular ducts

location? filled with? contain?

Answer 17

inside canals
filled w/ endolymph
contain cristae; receptors for dynamic equilibrium

Question 18

Cochlea

Answer 18

resembles a snail shell
transmit vibrations to Organ of Corti
-organ of hearing
Divided into 3 channels

Question 19

3 channels cochlea is divided into:

Answer 19

cochlear duct
scala vestibuli
scala tympani

Question 20

cochlear duct

definition? filled with?

Answer 20

continuation of membraneous labyrinth filled w/ endolymph

Question 21

scala vestibuli

filled with? location?

Answer 21

(chamber)

filled w/ perilymph, ends @ oval window

Question 22

scala tympani

filled w? location?

Answer 22

filled w/ endolymph, ends @ round window

Question 23

Organs of Corti

aka?

Answer 23

spiral organ

Question 24

organ of corti consists of?
which are....
covered by?
attached to?
produce?

Answer 24

16,000 hair cells (receptor cells)

• covered by tectorial membrane
• attached to supporting cells
• produce receptor potentials
  
  • conduct nerve impulses in vestibulocochlear nerve 8

Question 25

static equilibrium

senses? ex? involves?

Answer 25

senses position of head
senses linear acceleration/ deceleration (1 direction of movement) (seasick)
-EX) body moving in an elevator, @ cedar pt moving up & down
Involves: Utricle & Saccule
-contain macula (small thickened region)
-receptors for static equilibrium
-contain 2 cell types:
-supporting cells & hair cells

Question 26

supporting cells for static equilibrium

Answer 26

secrete thick gelatinous layer called otolithic membrane

• rests on hair cells
• otholiths: calcium carbonate crystals cover membrane

Question 27

hair cells for static equilibrium

Answer 27

sense receptors

Question 28

dynamic equilibrium

senses? helps w/? involves? contains?

Answer 28

(Ice skaters get used to this motion, dont feel lag time)
senses rotational motion
aids in maintaining balance
involves: Semicircular ducts
-at ends of each canal: ampulla
-contains cristae ampullaris (sensory hair cells)
- covered in gelatinous material- cupula

Question 29

what would happen if we had no static equilibrium?

bending over for example

Answer 29

no balance when head is down or while picking something up, we’d fall over

Question 30

is balance 1, 2 or 3 dimensional?

Answer 30

2 dimensional

static & dynamic

Question 31

Transmitting hearing to the brain steps (10)

Answer 31

1) sound waves enter external auditory canal
2) tympanic membrane vibrates
3) Vibrations sent form tympanic mem. to ossicles
- Malleus->Incus-> Stapes
4) Stapes hits oval window to transmit vibratiosn to cochlea
5) In cochlea; fluid pressure waves occur in perilymph in the scala vestibule (chambers in cochlea) (air->fluid)
6) Pressure waves transmitted from:
- scala vestibuli -> scala tympani -> round window
7) Pressure waves travel through perilymph of scala vestibuli & move into endolymp of cochlear duct
8) Endolymph pressure waves cause Organ of Corti receptor cells (hair cells) to bend & generate nerve impulses (vibratiosn go out of phyranx)
9) impulses sent to vestibulocochlear nerve
10) Auditory cortex of temporal lobe interprets sensory impulses (changes them into words we understand)

Question 32

hair cells of organ of corti convert what type of vibration/stimulus into what type of signal?

Answer 32

convert mechanical vibration (stimulus) into an electrical signal (receptor potential).

Question 33

sense receptor cells are known as?

Answer 33

hair cells