the ear

Question 1

action potential

Answer 1

electrical signal that occurs when neurons are excited.
* changes in air pressure from sound waves,

* we can have a single wave form (pure tone) but if we have lots of low and high frequencies we have a complex tone.

Question 2

cochlea (middle and inner ear)

Answer 2

coiled like a snail, causes membrane to flow in and out, and causes fluid to move back and forth. there are many changes in the physical nature as a result of sound, which causes fluid to move in the cochlea.

Question 3

basliar membrane (inner-middle ear)

Answer 3

scanning electron micrograph of cochlea- the cochlea is a long tube which is coiled tight. this hydraulic action is essential to convert fluid into a neural signal.

Question 4

organ of Corti:

Answer 4

• consists of different cell types and structure at the top called techtoral membrane, these rub against each other, which cause an electrical signal to be generated. the electrical changes in the hair cells is important. the physical changes lead to electrical changes in the hair cell.

Question 5

Transduction of auditory information in hair cells:

Answer 5

• if it bends one way no ions move across, as they move the other way ions can move into the hair cell. The level of a hair cell to not generate action potentials but they do impact the process of action potentials. physical movement of the sterocillia. cause changes to the next ions which cause the action potential to change.
  a lot more outer hair cells than the inner hair cells, inner hair cell often contact many spiral ganglion cells. damage innter hair cells might damage ability to hear.

Question 6

frequency changes along the basliar membrane

Answer 6

high frequency changes cause more vibrations at the base of the basilar membrane, and low frequency targers the apex of the basilar membrane.
* characteristic frequency of hair cells: rate of action potentials changs when we change the frequency of the sounds.

Question 7

totonic organisation of primary auditory cortex.

Answer 7

low frequency at tip high at base, the place along the basil ganglia represents the frequency.

Question 8

cochlear implants: based on the knowledge of place coding

Answer 8

some people are deaf because of damage to hair cells, electrodes inserted along the basilar membrane, stimulation causes spiral ganglion cells to generate action potentials.

Question 9

challenges of cochlear implants

Answer 9

• a large number of electrodes to reproduce sound well
• fast sound processors required to determine how much of each frequency is in sound especially with a large number of electrodes.
• not optimized for music
• our brain loses the capacity to make sense of novel input as we age.