A&P Speech - Chapter 9 - Anatomy of Hearing

Anatomy for Speech/Hearing

the ear is an energy __

transducer. converts acoustic energy to electrochemical

basic function of:

pinna/auricle

eam

otoscope

auricle localizes osund, made up of cartilage (conch,tragus protects entry,helix)

eam is ear canal

otoscope is intrustment used to see eam

tympanic membrane: func, made up of

barrier between outer and middle

transluenct grey

outer layer is rpitheal tissue

middle and inner layer is fibruous connective tissue

middle ear landmarks / func

3 bones malleus incus stapes

malleus is largest

middle ear is lined by epitheal tissue

FUNC dismishes sound for cochlea

joint between incus and stapes is

saddlejoint

muscles of the middle ear attach to

the bone (the malleus incus,stapes)

tympanic muscles (2 types )

1. stapedius muscle - embbeded in postieor wall of middle ear FUNC= stiffens whole ossicular chain by rotating footplate of stapes

2. tensor tympani muscle - stiffens whole chain by pulling on the handle of the malleus therby stiffening the TM

Both : contraction of these muscles reduces the strength of the signal reaching the cochlea, potentially protecting it from damage due to high signal intensity

most of TM is invested with ___tissue

fibrous.

except pars flaccida

anterior wall of middle ear

entrance to auditory tube, lines with mucosa, airates middle ear allows or equilibrium

middle wall of middle ear

cochlea and vestibular system

posterior wall of middle ear

mastoid ear cells acts as buffer in case of eustchian tube dysfunction. this the below the floor of the middle ear. if infected it is called: mastoiditis

the functial anterior point of seperation of the middle ear is the

tympanic mem

the functional posteriod point of seperation of middle ear is the

oval window

which nerve runs parallel to the middle ear cavity

facial nerve

which is the densest bone in the body

temporal bone 

describe the 3 parts of the osseous labyrinth

vestibule

semicircular canals

cochlea

what is the vestibule

connection btwn canals and cochlea - empty space

vestibular nerve passes thru here

This is located within the medial walls

STAPEDIUS MUSCLE INNERVATED BY

FACIAL NERVE

TENSOR TYMPANI MUSCLE INNERVATED BY

TRIGEMINAL NERVE

what is the very center of the cochlea called

apex

semiciruclar canals made up of what cells.

name 3 motions corresponding to what canal

sensory cells for movmt of body in space

1. posterior canal - vertical YES motion

2. lateral canal - horizontal NO motion

3. anterior canal - head to shoulder motion

round window communicates between the —- and the —-

scala tympani and middle ear

oval window comunicates btwn the —- and —-. it aligns with the ——

scala vestibuli and the middle ear

aligns with footplate of stapes

the cochlea houses ———- for ——

sensory organs for hearing 

cochlea core ?

which cranial nerve passes thru ?

name the 3 layers of the swirl 

modiulous

#8 - vestibulacochlea nerve

scala vesitbulii = above basilar membrane perilymph

scala tympani = below basilar memb. perilymph

scala media= middle, endolymph AKA COCHLEAR 

what is the osseuous cochlear labryinth

the actual swirl.

the scala tymp + vesitbuli

the 3 openings of the osseous labyrinth

round window

oval window

cochlear adeueduct

what does the cochlear aqueduct do

connect the upper duct of cochlea with the subarachnoid space of cranial cavity

the membranous labyrinth system includes (2)

vestibular system

cochlear duct

vesitbular system (not what u think)

endolympth - generaes impulse, responds to perilymph, houses vestib organ

ampulla - the sac underneath the semicirc canals, connects canals to uricle

cristas ampularis - receptor organ for movement, made up of cilia cells INSIDE AMPULLA

uricle

main bean under semi canals

sensory organ for hair cells and cilia

saccule

bean underneath the main bean(uricle).

contains maccula and otliths membrane

communicates WITH COCHLEA via endolymphatic duct thru ductus reunion

endolympathic duct connects saccule to utricle

endolymphatic duct

passageway (string like) between the two beans (utricle& saccule)

cochlear duct

surrrounded by scala tympani and vestibuli 

filled with endolymph and bony labryinth 

basilar membrane

wider, flaccid at apex

tenser and narrow at base

the “floor” of sscala media

reissners membrane separates

made up of (2)

scala vestibuli and scala media

1. stralia vascular - the tissue attached to the memb

2. spiral ligament - holds potassium used by hair cells. disruption of this leads to HL

tectorial membrane forms cover over…

this location is important becus…

organ of corti

THIS IS WHERE ACOUSTIC STIMULI IS PROCESSED

what are the two membranes that surround the cochlear duct

reissners - ceiling

basilar - floor

types of cells in organ of corti and function

inner hair cells - single row of tear drop cells (SENSORY receptors) 1 HAIRCELL TO 10 CN#8

outer hair cells - 3-4 rows of test tube cells (hears soft sounds)

MANY HAIRCELL TO 1 CN

termination of outer hair cells are mostly all from ____ axons from brain cells

EFFERENT

AKA AWAAYYYYYYYY

Afferent innervation 

TO an organ 

organ like the brain!

Efferent inneration

AWAY an organ

(organ like the brain!)

hair cells of cochlea recieve _____ innervation

BOTH AFFERENT AND EFFERENT

what circuit detects, controls, responds to background noise

olivary cochlear bundle

(crossed and uncrossed)