Special Senses of The Ear Flashcards
Functions of the ear (2)
enables the sense of hearing
provides a sense of equilibrium
Anatomy of the ear
-Outer (External) Ear: contains? (3)
Auricle or Pinna
External Auditory Canal (Meatus)
Tympanic membrane (eardrum)
Auricle or Pinna
location? function? contains?
(cuff hand to hear better) (Mikey Mouse has big auricles)
exterior ear structure
collects sound waves
Lobule- ear lobe
External Auditory Canal (Meatus)
size? location? function? contains?
(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)
Tympanic membrane (eardrum) description? function?
semi-transparent membrane
sound waves cause it to vibrate & causes ossicles to vibrate
Anatomy of the ear
Middle Ear: contains? (4)
Auditory ossicles Round window Oval window auditory tube (eustachian tube)
Auditory ossicles
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
Round window
below oval window
involved in air pressure regulation
(opening mouth, hear pop bc pressure builds in plane)
oval window
opening in wall of middle ear
stapes connected by ligaments to window
Auditory tube (eustachian tube) functions? contains? location?
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
Anatomy of the ear
-Inner (internal) Ear: divisions? (2)
aka?
aka labyrinth (series of canals) 2 Divisions: Osseous (Bony) Labyrinth Membraneous Labyrinth
Osseous (Bony) Labyrinth
filled with? location?
encloses the inner layer - membraneous labyrinth
filled w/ PERILYMPH
-similar to spinal fluid
What are the 3 layers the Osseous (Bony) Labyrinth is divided into?
1) Vestibule (semicircular canals & cochlea go into this)
2) Semicircular canals (equilibrium)
3) Cochlea (hearing, snail)
Membraneous Labyrinth
description? contains? filled with?
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
Vestibule
description? location? contains? function?
(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
Semicircular Canals
description? location? contain?
anterior & posterior vertical canals
lateral horizontal canal
end of each canal enlargement called ampulla
contain receptors for equilibrium
Semicircular ducts
location? filled with? contain?
inside canals
filled w/ endolymph
contain cristae; receptors for dynamic equilibrium
Cochlea
resembles a snail shell
transmit vibrations to Organ of Corti
-organ of hearing
Divided into 3 channels
3 channels cochlea is divided into:
cochlear duct
scala vestibuli
scala tympani
cochlear duct
definition? filled with?
continuation of membraneous labyrinth filled w/ endolymph
scala vestibuli
filled with? location?
(chamber)
filled w/ perilymph, ends @ oval window
scala tympani
filled w? location?
filled w/ endolymph, ends @ round window
Organs of Corti
aka?
spiral organ
organ of corti consists of? which are.... covered by? attached to? produce?
16,000 hair cells (receptor cells)
- covered by tectorial membrane
- attached to supporting cells
- produce receptor potentials
- conduct nerve impulses in vestibulocochlear nerve 8
static equilibrium
senses? ex? involves?
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
supporting cells for static equilibrium
secrete thick gelatinous layer called otolithic membrane
- rests on hair cells
- otholiths: calcium carbonate crystals cover membrane
hair cells for static equilibrium
sense receptors
dynamic equilibrium
senses? helps w/? involves? contains?
(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
what would happen if we had no static equilibrium?
bending over for example
no balance when head is down or while picking something up, we’d fall over
is balance 1, 2 or 3 dimensional?
2 dimensional
static & dynamic
Transmitting hearing to the brain steps (10)
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)
hair cells of organ of corti convert what type of vibration/stimulus into what type of signal?
convert mechanical vibration (stimulus) into an electrical signal (receptor potential).
sense receptor cells are known as?
hair cells
