anatomy and physiology unit 2

transverse plane

cut horizontally below nose

medial

closer to middle

lateral

closer to edges

sagittal plane

cut down the nose into right vs. left

posterior

towards the back

anterior

towards the front

coronal plane

cut into front and back

superior

upwards

inferior

downwards

dextral

right

sinistral

left

ipsilateral

on the same side

contralateral

on the opposite side

proximal

near point of reference

distal

further from point of reference

modes of operations of ear

acoustic, mechanical, mech/hydromech/electrochem, electrochemical

impedance matching

process of equating output impedance of one component to the input impedance of another

impedance matching of auditory system

air to TM, TM to ossicular chain, ossicular chain to cochlear fluid

acoustic units

pressure

mechanical units

velocity

hydromechanical units

displacement

electrochemical units

electrical potential

transfer function

process of filtering input to produce different output

parts of inner ear

pinna, external canal, TM

extrinsic muscles

posterior, superior, anterior auricular muscles

intrinsic muscles

muscles of helix and antitragus

makeup of ear canal

first 2/3 cartilaginous, last 1/3 bone

adult canal info

25 mm long, 8mm diameter, pointed superiorly

infant canal info

14 mm long, <5mm diameter, pointed horizontally

cough reflex

triggered by mechanical stimulation of auricular branch of Vagus nerve

TM info

10 mm diameter, .08 mm thick

TM tissue layers

cutaneous, fibrous, internal mucosa

radial fibers

become more concentrated as they converge on manubrium

spiral fibers

thicker towards periphery and thinner at umbo

pars flaccida

loose but thick

pars tensa

tense but thin

TM angles

the acute angle creates 10 dB differences from top to bottom

TM motion

low frequencies = standing waves, high frequencies = traveling waves

at high frequencies, the TM moves

at different times from other parts, which creates the ripple effect

where are all resonances summed up on the TM

the umbo

how to measure resonance of ear canal

probe (in the ear canal), reference microphone (outside ear), sound source (front/side of head)

how is the sound level at reference vs. probe plotted?

as function of frequency

external ear effect/sound field transform

combination of sound interacting with head, torso, pinna, and ear canal (mostly ear canal)