4.3 the auditory system, sense of touch, the gustatory system and the olfactory system

Question 1

sound waves

Answer 1

provides basic input for our auditory experiences
sounds waves are simply the effect of air molecules on some physical disturbance
-frequency
-amplitude

Question 2

frequency

Answer 2

we experience perceptually as the pitch of a sound
based on the speed by which air molecules are displaced by the pressure of the original physical event which initiates the sound. the pressure from a sound pushes the molecules out as it emanates from the source, then the molecules return to their original position after the pressure travels beyond their location
shorter wavelength (Hz) = higher frequency sounds (high pitched)
longer wavelength (Hz) = lower frequency sounds   (low pitched)

Question 3

are there limits to what we are able to hear ?

Answer 3

yes ! humans can hear sounds from 15 Hz which is the absolute lowest, and about 20,000 Hz at the highest

Question 4

amplitude

Answer 4

-height of the sound wave from the mid point
sound amplitude in decibels (dB)
-amount of displacement in the air molecules caused by sounds origin
-high amplitude sounds are louder than low amplitude sounds

Question 5

Ear consists of _____ parts

Answer 5

3

• pinna
• auditory canal
• eardrum

Question 6

pinna

Answer 6

outer ear

part of ear we see attached to our head

Question 7

auditory canal

Answer 7

tube extending from the pinna to the eardrum

Question 8

eardrum

Answer 8

sound strikes the eardrum and vibrate the eardrum and the same frequency and amplitude as the sound wave

Question 9

ossicles

Answer 9

three little bones connected to the eardrum
1st is malleus (or hammer)
2nd is incus (or anvil)
3rd is stapes (or stirrup)
the vibrations of the eardrum causes these bones to also move as the same frequency and amplitude as the sound waves, and mainly function to provide a stronger signal from the eardrum before passing it down into the inner ear

Question 10

cochlea

Answer 10

receives information about the sound waves from a connection with the stapes bone
filled with fluid and the interior of the cochlea contains a structure called the basilar membrane

Question 11

basilar membrane

Answer 11

flexes in response to the tapping pattern provided by the stapes bone , which causes movement of the fluid inside the cochlea, this movement displaces hair cells along the basilar membrane, these hair cells are connected to the dendrite of neurons that send signals about sounds to the brain. these cells get bundled together into auditory nerves that project first to the brains thalamus then on to the primary auditory cortex in our temporal lobe

Question 12

place theory of hearing

Answer 12

higher frequency sounds produce more displacement of hair cells nearest to the stapes
lower frequency sounds produce more displacement of hair cells further along the basilar membrane
-the idea is that the brain uses which hair cells are sending the strongest signals to determine whether a sound is higher or lower in pitch

Question 13

frequency theory of hearing

Answer 13

the stapes taps against the cochlea at a frequency that matches the frequency of the sound wave striking the eardrum
the basilar membrane vibrates at this same frequency, causing hair cells along the basilar membrane to vibrate at that frequency too
*the theory is that hair cells send signals to the neurons connected to them according to the frequency that they are vibrating.
good explanation for lower frequency
*such signals would allow us to perceive the pitch of a sound in a way that relates directly to the frequency of a sound

Question 14

volley principle

Answer 14

many neurons working as a team could alternate their firing to achieve a rate of firing well above 1,000 times per second
good explanation for lower frequency

Question 15

sound localization

Answer 15

finding where a sound is coming from
sound typically arrives to each of our ears at slightly different times and we can use this to get an idea of where the sound is coming from, sound coming from the right will reach our right ear faster then our left
sounds will arrive at a higher intensity to whatever ear is oriented toward the origin of the sound, sound coming from the left will be received by your left ear at a higher amplitude than when it arrives at your right ear, your head will dampen the sound before it reaches the right ear, called sound shadow

Question 16

sound shadow

Answer 16

head blocking/ dampening sound before sound reaches other ear

Question 17

inferior colliculi

Answer 17

structure in brain responsible for processing info about the location of sound and guiding our orientation to new sounds that warrant our immediate attention

Question 18

primary auditory cortex and secondary auditory cortex

Answer 18

once signals from the ears reach the primary auditory cortex in the temporal lobe, cells in that region are specialized to fire selectively in response to sounds corresponding to specific frequencies
structure of the region is very organized with neurons that respond to specific higher frequencies at one end and those that respond to lower frequencies at the other end the neurons in the primary auditory cortex project to the secondary auditory cortex for further processing, ultimately the brain does with this info results in all of our rich experiences of sound and our capacity to use sound perception to understand human speech

Question 19

sense of touch

Answer 19

touch senses in our skin, muscles and joints give us info about the amount of pressure being applied to the surface of our bodies as well as info about the temperature of objects that come into contact with our skin

• haptics
• kinesthesis

Question 20

somatosensory cortex

Answer 20

touch sensors send signals to the somatosensory cortex in the brains parietal lobes, sensitivity to pressure differs for different parts of the body.
we can easily perceive two points pressing close to one another against two different spots on our hand but two points of pressure at the same distance apart against other regions such as on our back is only experienced as one, these differences in sensitivity simply reflect the difference in the concentration of touch sensors across different regions of our bodies

Question 21

haptics

Answer 21

active exploration of objects to learn their properties

-how the surface effects our touch sensors

Question 22

kinesthesis

Answer 22

sensors in our muscles, joints, and tendons that gibe us a sense of the position of our body parts in space
-whether a pear is real or plastic

Question 23

nocicpetion or pain perception

Answer 23

fast fibres
slow fibres
these get sent through the spinal cord

Question 24

fast fibres

Answer 24

for sharp intense pain caused by injury

Question 25

slow fibres

Answer 25

for the persistent, throbbing pain that persists after an injury occurs

Question 26

gate control theory

Answer 26

the idea that some spinal cord cells send pain signals to the brain and others that inhibit transmission of pain signals to the brain being in a state of arousal (or when distracted by other sensations) seems to activate the spinal cord fibres that suppress transmission of pain signals -this explains why kicking a corner hurts more then tripping during a game

Question 27

phantom limb pain

Answer 27

people who have lost a limb sometimes experience cramping shooting stabbing or burning pains coming from the limb that no longer exists. the absence of activity in the part of the somatosensory cortex that register sensations from the missing limb, causes a hyper sensitivity in the neurons that are connected in that region and those neurons send pain signals in response to the absence of signals from the somatosensory cortex

Question 28

mirror therapy

Answer 28

helps phantom limb pain position mirror to make it look like there are both limbs this gives them the feeling they can move their amputated limb again which settles down the pain signals that cause phantom limb pain

Question 29

the gustatory system

Answer 29

basic components of taste are : salty, sour , bitter, sweet and umami

Question 30

papillae

Answer 30

bumps on our tongue capable of regenerating and they do every ten days represent our sensory organs for taste there are diff taste buds for diff primary tastes connected to taste buds are the dendrites of neurons that send signals about the presence of dissolved molecules that come into contact with taste buds

Question 31

signals from the tongue project first to the ______ then to the ___________, located in the ________

Answer 31

thalamus , primary gustatory cortex region, frontal lobes | -this leads us to identify familiar tastes

Question 32

secondary gustatory cortex

Answer 32

also receives messages and provides the emotional experiences that accompany taste sensations the determine whether you reaction to what you are tasting is emotionally positive or negative

Question 33

olfactory system

Answer 33

sense of smell substances in our environment release little bits of themselves into the air, these molecules float around in the air and find their way up into our noses, where they bind with receptors at the top of our nasal cavity signals from our smell receptors project into our brain structure directly above called the olfactory bulb

Question 34

olfactory epithelium

Answer 34

in the nasal cavity contains a layer of cells that host little hair cells called cilia cilia contain sites that bind with particular molecules , we have a 1000 different types. the different smells we experience rely on the combined signals from more than one types of these receptor sites

Question 35

olfactory bulb

Answer 35

connects with a number of diff areas of the brain which work together to provide us with the ability to identify smells and to experience positive and negative emotional reactions to them

Question 36

auditory system

Answer 36

our ears collect sound waves, and our brains use that info to identify the source and interpret the content and location of noise. or just to enjoy the experience of listening responsible for human communication throughout history