Auditory Pathway

Question 1

What does the cochlear canal coil around and what is inside

Answer 1

coils around bony structure called modiolus

-main spiril ganglion inside

Question 2

What are the 2 chambers of the cochlear cannal

Answer 2

sup-Scala vestibuli

lower- Scala tympani

(both have perilymph inside)

Question 3

What is located between the 2 chambers of the cochlear cannal

Answer 3

cochlear duct with endolymph inside

Question 4

Where do the scala vestibuli and scala typani communicate with eachother

Answer 4

Helicotrema at tip of cochlear canal

Question 5

How does vibrations from stapes travel thru cochlear cannals

Answer 5

1.connects with scala vestibuli (creates vibrations withing perilymph)
2; The vibrations will reach tip of cochlear duct and will travel to scala tympani and travel to the base where there is a communication bw inner and middle ear (round window)

Question 6

What is the apical portion of the hair cells contacting+ what do they sense

Answer 6

Apical portion have steriocillia which contacts tectorial membrane and sense vibrations in periplymph

Question 7

What do the basal pole of hair cells have

Answer 7

• Vibrations of perilymph travel to basilar membrane and it vibrates organ of corti, steriocilia move relative sparking action potential
• Basal pole of hair cells have dendrites of cochlear nerve

Question 8

Where are higher pitches regestered better and lower pitches

Answer 8

Higher pitches at base

lower pitches at apical portion

Question 9

What are the 1st order neurons of the auditory pathway

Answer 9

Neurons in the spiril ganglion

Question 10

Path of axons of cochlear nerve as it enters brainstem

Answer 10

Axons exit ptetrous part of temp bone and form cochlear component of vestibularcochlear nerve and enter brainstem at lat most part of pontomedullary groove dividing into ant and post branch

Question 11

What is the 2nd order neuron of the auditory pathway

Answer 11

Ant and post cochlear nucleus

Question 12

What is the 3rd order neuron of the auditory pathway and path after

Answer 12

Axons from ant/post cochlear nuc project bilaterally to trapezoid body and sup olivary nucleus.

All ascend forming lateral lemniscus

Question 13

what is the 4th order neuron of the auditory pathway

Answer 13

Most of the ascending fibres synapse on inf colliculus (small amount skip and pass thru inf brachium to go right to MGB)

Question 14

What is the 5th order neuron of the auditory pathway

Answer 14

MGB-

Question 15

Path from 5th order neuron of auditory path to end location

Answer 15

fibres from here bundle up as geniculotemporal fibres and travel thru sublenticular part of int capsul contributing to aucustic radiation and project to sup surface of temporal gyrus (herchles gyri)