have you heard the news??? it’s ear time!!. trivia question what are the smallest bones in the...
TRANSCRIPT
Have you
heard the news???
It’s
ear time!!
Trivia QuestionTrivia QuestionWhat are the smallest bones What are the smallest bones
in the body?in the body?OssiclesOssicles
OssiclesOssiclesThese bones are fully developed at These bones are fully developed at
birth!birth!
How the Ear Works!AHow the Ear Works!An Animation!!n Animation!!
Ear has 2 main functionsEar has 2 main functionsHearingHearingEquilibriumEquilibrium–StaticStatic–DynamicDynamic
StructureStructureEar has three main Ear has three main sectionssections–Outer earOuter ear–Middle earMiddle ear–Inner earInner ear
Outer EarOuter Ear PinnaPinna
– Ear flapEar flap– Collects sound wavesCollects sound waves– Directs them to the…Directs them to the…
Auditory canalAuditory canal– Carries sound to the eardrumCarries sound to the eardrum– Protects earProtects ear
Ear wax – made by Ear wax – made by specialized sweat glandsspecialized sweat glands
Traps foreign particlesTraps foreign particles
Middle EarMiddle Ear Begins at ear drum (tympanic Begins at ear drum (tympanic
membrane)membrane) Air filledAir filled Contains Contains ossiclesossicles
– Hammer (malleus)Hammer (malleus)– Anvil (incus)Anvil (incus)– Stirrup (stapes)Stirrup (stapes)
Strikes oval windowStrikes oval window Oval window much smaller than Oval window much smaller than tympanic membrane – helps amplify tympanic membrane – helps amplify soundsound
Eustachian tubeEustachian tube–Connects middle ear Connects middle ear with nose and mouthwith nose and mouth
–Allows for Allows for equalization of equalization of air air pressurepressure
Inner EarInner Ear 3 main structures3 main structures
1. Vestibule1. Vestibule Contains 2 sacs – utricle and Contains 2 sacs – utricle and sacculesaccule
Contains fluid, hair cells, Contains fluid, hair cells, and Otoliths and Otoliths CaCO CaCO33 (s) (s)Stimulate nerve fibresStimulate nerve fibres
Detects head position Detects head position –Static equilibriumStatic equilibrium
2. Semicircular canals2. Semicircular canals Fluid filledFluid filled 3 canals3 canals
–Horizontal, vertical, Horizontal, vertical, diagonaldiagonal
movement & balancemovement & balance Each canal has an Each canal has an ampullaampulla– cilia cilia receptor cells receptor cells
Dynamic equilibriumDynamic equilibrium
3. Cochlea3. Cochlea Liquid filledLiquid filled Vibrations Vibrations waves waves
Converted to nerve impulsesConverted to nerve impulses 3 sections3 sections
Cochlear ductCochlear duct contains contains organ of cortiorgan of corti with with ciliacilia
Scala tympaniScala tympani (tympanic canal) (tympanic canal) Scala VestibuliScala Vestibuli (vestibular canal) (vestibular canal)
Organ of CortiOrgan of Corti– Contains cilia which stimulate nervesContains cilia which stimulate nerves– Cilia attached to cells in the basilar Cilia attached to cells in the basilar
(bottom) membrane and touch the (bottom) membrane and touch the tectorial membrane (top membrane)tectorial membrane (top membrane)
– Sensory Hair cells – respond to Sensory Hair cells – respond to vibration of basilar membranevibration of basilar membrane
– An An action potentialaction potential develops in develops in sensory nervessensory nerves
– Sending auditory info to brain Sending auditory info to brain (temporal lobe)(temporal lobe)
Pitch and Pitch and LoudnessLoudness
Stimulation of cells in different Stimulation of cells in different areas cause different pitchesareas cause different pitches
Cochlea narrow in beginningCochlea narrow in beginning– Hair fibers very rigidHair fibers very rigid– Responding to high frequencyResponding to high frequency– Basilar membrane vibratesBasilar membrane vibrates– Sound dies fastSound dies fast
Cochlea eventually gets widerCochlea eventually gets wider– Hair fibers more elasticHair fibers more elastic– Responding to low freqResponding to low freq– Sound resonates (lasts longer)Sound resonates (lasts longer)