3.1 A and P Inner Ear Part 1

the inner ear is made out of what 2 spaces:

osseous bony labyrinth.

membranous labyrinth.

together these 2 make up the cochlear duct.

what are the two fluids spaces of the inner ear?

endolymph (in membranous labyrinth) and perilymph (in osseous labyrinth).

what 2 structures does inner ear contain?

cochlea (organ of hearing)

and

vestibular system (organ of motion and gravity)

what makes endolymph?

the endolymphatic sac

where does endolymph go?

cochlea and vestibular system.

in petrous part of temporal bone

location of perilymph relative to endolymph system

Perilymphatic fluid surrounds flexible endolympathic system.

perilymph is made and supplied by

cochlear aqueduct or CA and is in turn supplied by CSF

endolymph ionic composition

high concentration of potassium than sodium.

perilymph ionic composition

Perilymph contains high concentration of sodium than potassium.

osseous lab is continuous with

Periphery of osseous labyrinth is continuous with petrous part of temporal bone.

where is the endolymph sac found?

near the dura of the brain

cochlea is made out of 3 compartments or ducts

scala vestibuli.

scala media.

scala tympani.

two membranes separate scala media from other scala compartments

Reissner and basiliar membrane.

describe the cochlea structure from the oval window to the scalas

The oval window is the start of the scala vestibula which contain the fluid filled compartments.

Scala tympani is continuous with scala vestibuli and both contain perilymph.

That region in which they are joined is called the helicotrema or at the top of the cochlea.

scala media contains what fluid

endolymph

scala vestibuli and tympani contain what fluid

perilymph

base of cochlea resonates with what frequencies

higher frequencies

middle neurons in cochlea respond to what frequencies

mid

apex neurons in cochlea resonate with what frequencies

lower frequencies

modiolas

spiral repeating structures.

same whether in base or apex.

what is a safe mechanism preventing two fluids from mixing?

specialised gap junctions

basilar membrane contains what organ?

organ of corti (organ of hearing) which separates from scala

what is the stria vascularis?

on the periphery.

Regulates endolymph and its concentration.

spiral ganglion neuron also called

auditory neuron or cochlear neurons.

a bit like the hair cells these neurons are spiralling.

Communicate with hair cells (activating them and cause transduction of sound wave into electrical impulse which is sent up to the brain for processing).