SNS

Question 1

why is the auditory system regarded as being remarkable?

Answer 1

it can perform biologial tasks with energies and dimensions that rech the range of quantum physics

Question 2

what sound unit can the auditory system detect?

Answer 2

it can detect sound-induced displacement in the order tf the picometer

Question 3

give 4 main things that the auditory system can do which no other system in the human body is capable of?

Answer 3

• encompasses frequencies from 20Hz to 20kHz
• allows us to detect sound in space because of microseconds differences in the arrival of sound between the 2 ears
• displays a trillion-fold in acoustic power (from the drop of a pin to the roar of a jet engine)
• actively amplify sound by several hundred fold

Question 4

what is the most common sensory deficit in the human population? what can this cause i.e. why is it important to tackle this?

Answer 4

hearing loss is the most common and we are still very far from a cure
people with deafness become socially isolated, go into depression and then they develop a decline
there is now evidence that this will decrease the development or other important areas

Question 5

what is the current best cure for hearing loss?

Answer 5

hearing aids/cochlear implants
cochlear implants are the best of teh 2 however the level of hearing that they are able to get after having the implants is still not very good

Question 6

how many people have hearing loss in the UK?

Answer 6

there are ~11 million people with hearing loss in the UK- worldwide this is estimated to be ~360 million. there are 50,000 children with hearing loss in the UK
an estimated 1 million people in the UK have severe or profound hearing loss and more than 40% of people over 50 years old having hearing loss, rising to 71% of people over the age of 70

Question 7

why is sensory transduction necessary for the brain?

Answer 7

the brain only understands electrical signals so you need a process of transduction - sensory to electrical and electrical can go to the brain to interpret this signal.
need a very specialised receptor to do the job of detecting a stimulus to convert it into an electrical signal
all sensory receptors are signal transducers

Question 8

what is the link between sensory receptors and signal transducers?

Answer 8

sensory receptors are signal transducers

Question 9

describe the process of sensory transduction

Answer 9

have sound going into our ear and sound causes a displacement of this air like structure
when you displace this structure, on top of this ear like structure there are channels and so when you move/displace the bundle, the channel opens
when the channel pens because of the bundle being stimulated y sound, you change the membrane permeability for this sensory receptor
this happens because ions flow through the membrane and so you’re generating a receptor current
the ion that flows through the current of the transduction channel is K because there is a solution around the stereocilia which is rich in K. when you have a K based current that goes through the cell, you are generating a receptor potential and is the receptor becomes depolarised. this is necessary because then you activate Ca channels which is important for neurotransmitter release onto the nerve
then, there is a burst f activation f the afferent nerve which leads to sensory perception and integration in the brain (e.g. with the sensory system)

Question 10

what are the 4 types of information that the sensory receptors transmit?

Answer 10

modality, location, integrity and duration

Question 11

describe the modality type of sensory receptor transmission

Answer 11

The type of stimulus or sensation they transduce (e.g. vision, gearing and taste)
Transform one form of energy into another
E.g. hearing, balance, touch pressure etc.

Question 12

what are the different sensory receptors?

Answer 12

photoreceptors, olfactory receptors and taste receptors

Question 13

describe the location type of sensory receptor transmission

Answer 13

sound location is the ability to localise sound in space

this is possible because of 2 mechanisms

Question 14

what is interaural timing differences (ITDs)?

Answer 14

the difference in arrival time of sound from at the 2 ears as small as 10 microseconds
this is enough for the brain to understand where the sound is coming from
mainly used for low frequency sound

Question 15

what is interaural level differences?

Answer 15

the difference in the intensity of sound at the 2 ears as small as 1-2dB
mainly used for high frequency sound

Question 16

comparing interaural level and timing differences, how will this affect the ears?

Answer 16

the ear closest to the sound will be bigger than the other for both
most species use strategies but it depends on the animals haring rage and head size

Question 17

how can localisation be understood in terms of tactile?

Answer 17

the smaller the receptor field, easier it is to distinguish how far a sound is/where it is coming from

Question 18

describe the intensity type of sensory receptor transmission

Answer 18

intensity - the larger the stimulus, the stronger the response of the receptor and the stronger the firing of the auditory neurones. stimulus intensity rises and firing frequency of sensory nerve fibres rise

Question 19

describe the duration type of sensory receptor transmission

Answer 19

a. Has 2 types of receptors: tonic receptors and phasic receptors
b. Tonic receptors are able to respond throughout the stimulation. Useful because you need to respond to sound continuously. These are in the auditory system and so they have slow adaptation
c. Phasic receptors are activated at the beginning of the stimulation and then inactivate.

Question 20

what are the 2 types of receptors for duration? and what are their differences

Answer 20

tonic receptors - slow adaptation

phasic receptors - burst, fast adaptation

Question 21

what is sound?

Answer 21

Sound is produced by vibrating particles, which cause slight changes in air pressure
These air pressure changes travel as waves through the air and produce sound

Question 22

what happens when sound is produced

Answer 22

there is a period of rarefraction and a compression in the air
sound energy is travelling in space, but the air itself is not travelling
only the disturbance in the air is travelling

Question 23

what are the 2 main properties of sound?

Answer 23

frequency and intensity (pr amplitude)

Question 24

describe frequency as a property of sound

Answer 24

the number of compressed or rarefield patches of air that pass by our ears each second. expressed as hertz and perceived as pitch
the number of this cycle (rarefaction and compression) in sound waves each second determines the frequency in Hz and is perceived as pitch

Question 25

describe intensity as a property of sound

Answer 25

air pressure differences between peaks and troughs
expressed as decibels, this is a logarithmic scale
perceived as loudness

Question 26

how loud are sounds around us? i.e. in a working place

Answer 26

in a working place, when sound reaches above 80dB-120dB, people use ear protection
this is in places like workshops etc. because it can damage your ears