Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Behavioral Neuroscience > Chapter 9- Hearing, taste, and smell > Flashcards

Chapter 9- Hearing, taste, and smell Flashcards

1
Q

What is sound?

A

When we detect sound, we are actually detecting changes in air pressure that travel through the air to the ear (represented as a wave)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Amplitude

A

How big the wave is, measured as sound pressure. Amplitude is perceived as loudness, so a large amplitude= louder sound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Frequency

A

Measured in Hertz (Hz). How many cycles of up and down you have in one second. The more cycles you have, the higher the frequency and the higher the pitch (how frequency is perceived).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which frequency can most people perceive?

A

Most people detect 20-20,000 Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What makes up the outer ear?

A

The pinna and ear canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Pinna

A

The external part of the ear that you can see. Its function is to funnel sound waves into the ear canal. It also enhances certain frequencies- ridges on the outer ear amplify vibrations- the pitches of human speech especially. Sound waves propagate down the ear canal to the tympanic membrane.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which structure marks the start of the middle ear?

A

The tympanic membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which structures make up the middle ear?

A

The tympanic membrane and the ossicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the function of the tympanic membrane?

A

Vibrations in the tympanic membrane at the same frequency as the sound, cause 3 ossicles (malleus, incus, and stapes) to move (also at the same frequency). Amplifies sound- vibration makes the sound louder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which structures control the contact between ossicles?

A

Contact between ossicles is controlled by two muscles, the tensor tympani and stapedius muscles. This creates a protection mechanism from loud sounds that could be damaging- causes the ossicles to vibrate less. They also mute self made sounds (from inside the body)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

3 ossicles

A

Stapes, incus, and malleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Stapes function

A

Stapes (third ossicle) contacts oval window of the cochlea (with the same frequency). It transfers vibrations to 3 fluid filled canals in cochlea.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Cochlea structure

A

The cochlea makes up the inner ear. It is a spiral of 3 parallel fluid filled canals- the scala vestibuli, scala media, and scala tympani. The round window is a membrane separating the scala tympani from the middle ear. The basilar membrane and tectorial membrane separate the canals (scala vestibuli, media, and tympani).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Function of the basilar membrane

A

Sounds travel along the basilar membrane, but only parts of the basilar membrane will vibrate depending on the frequency of the sound. High frequencies vibrate the narrow, stiff base of the cochlea, and low frequencies vibrate the wide, floppy apex.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Organ of corti

A

A structure located on the basilar membrane of the cochlea. It contains inner and outer hair cells, which help to transduce sound waves into neural activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Inner hair cells

A

IHCs detect the frequency of the sound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Outer hair cells

A

OHCs help discriminate between similar frequencies and assist with IHC signaling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Hair cells

A

Hair cells transduce sound waves into neuronal activity. They have 50-200 stereocilia (hairs) that will vibrate during sound transduction. Hair cells are not neurons and will not generate an action potential themselves- they synapse with auditory nerve fibers, which will generate an action potential to send to the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do inner hair cells transduce sound?

A
  1. Vibrations of the basilar membrane bend stereocilia
  2. Tip links stretch and will open ion channels
  3. Calcium, potassium depolarize IHC. The depolarization does not trigger an action potential. If big enough, the depolarization will open voltage gated calcium channels and release NT
  4. Release NT onto auditory nerve (mainly Glutamate)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What can damage hair cells?

A

Loud, continuous noise like loud music damages the hair cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Tonotopic organization

A

All levels of the auditory pathway are spatially arranged in a map according to the auditory frequencies they respond to. The organization begins in the cochlea, since frequency is ordered along the length of the basilar membrane. This is observed when the responses of auditory brain regions to tones of different frequencies are mapped. This is critical for sound localization.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Tuning curve

A

Auditory nerves have distinctive receptive fields or tuning curves. The lower the decibels, the more sensitive the auditory nerve is to the sound. Each auditory neuron responds to a specific frequency, but the neuron responds to a broader range of frequencies for more intense stimuli. A neuron is said to be “tuned” for the stimulus that evokes the greatest response.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Hair cells synapse onto

A

The vestibulocochlear nerve (the 8th cranial nerve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the pathway of auditory information to the brain? (4)

A
  1. Hair cells synapse onto vestibulocochlear nerve (8th)
  2. 8th nerve synapses onto cochlear nucleus in brain stem. This is different from touch and pain- most information crosses to the other side, but some stays on the same side
  3. Info travels to both superior olivary nuclei
  4. Inferior colliculus (primary auditory centers of midbrain), then medial geniculate nucleus (thalamus), then auditory cortex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Where does auditory information cross over?

A

The information that crosses over will cross at the superior olivary nuclei.

26
Q

Which is the first area of processing for auditory information?

A

The inferior colliculus is the first area of processing

27
Q

What is the significance of auditory information going to both sides of the brain?

A

Information going to both sides of the brain means that we can hear what’s going on on both sides- information can be combined to locate sound

28
Q

Inferior colliculus

A

This area of the brain exhibits tonotopic organization, which is used for sound localization. Processes intensity, frequency, and duration of sound in order to localize where sound is coming from. Intensity differences (loudness) occurs because one ear is pointed more directly toward the sound source. Sounds also arrive at different times when one ear is closer to a sound than the other

29
Q

Auditory cortex

A

Identifies complex sounds that have many sub parts (vocalizations). Voices, for example, are composed of many frequencies. This area of the brain helps with interpreting more complex sounds. The auditory cortex also exhibits tonotopic organization.

30
Q

Types of deafness (3)

A
  1. Conduction
  2. Sensorineural
  3. Central
31
Q

Conduction deafness

A

Disorders of the outer/middle ear that prevent vibrations from reaching the cochlea and basilar membrane

32
Q

Sensorineural deafness

A

Originates from cochlear or auditory nerve lesions, hereditary disease of hair cells. Information isn’t transduced correctly by the cochlea (happens with damaged hair cells), or it is transduced but the auditory nerve isn’t bringing it to the brain. This is the type of deafness that results if you listen to loud music for too long.

33
Q

Central deafness

A

Hearing loss caused by brain lesions (such as stroke), with complex results. Not processed correctly in the auditory cortex

34
Q

Cochlear implants

A

Have a microphone that’s wired into the head and goes into the cochlea. The microphone picks up the frequencies the ear would usually pick up and skips conduction and transduction so the electrical information can be sent to the auditory nerve directly. The implant still relies on the auditory nerve to work

35
Q

What type of deafness can be helped by a cochlear implant?

A

Can help conduction and sensorineural deafness (but more likely sensorineural). Usually with conduction deafness you would just have a hearing aid

36
Q

How many odorants can humans discriminate?

A

Humans can discriminate over 1 trillion odorants

37
Q

Any 2 people differ in their expression of different odor receptors by

A

30%

38
Q

Olfactory epithelium

A

A thin layer of cells covered in mucus, where the odorants arrive during inhalation. Contains olfactory receptor neurons.

39
Q

Cells found in the olfactory epithelium (3)

A
  1. Olfactory receptor cells (6 million)
  2. Supporting cells
  3. Basal cells
40
Q

Basal cells

A

Allow the regeneration of neurons. If an olfactory receptor cell is destroyed, an adjacent basal cell differentiates and becomes a neuron, extending dendrites to the mucosal surface and axons to the brain that will synapse in the correct part of the olfactory bulb. The olfactory epithelium can also regenerate and connect to the olfactory bulb if damaged. Hippocampus and olfactory bulb seem to be the only 2 places where neurons can be regenerated. Probably occurs because olfactory neurons are exposed to many different irritants, and are therefore easily damaged- the neurons can replace themselves when they die every 14 days or so

41
Q

Olfactory neuron characteristics (3)

A

Olfactory neurons have

  1. Dendrite to olfactory mucosa with cilia extends from the dendritic knob- the axon projects up into the glomerulus
  2. Unmyelinated axon to olfactory bulb
  3. Metabotropic receptors on cilia and knob
42
Q

Glomeruli

A

The olfactory bulb is organized into spherical neural units called glomeruli. They are clusters of mitral cells. A glomerulus receives input from olfactory neurons with same receptor type- separated by function in olfactory bulb

43
Q

Olfactory bulb

A

The olfactory bulb is a structure in the anterior part of the brain where olfactory receptors terminate. This is where the axons of olfactory neurons synapse with mitral cells.

44
Q

The axons of olfactory receptor cells combine to form

A

The olfactory nerve

45
Q

Olfactory neuron structure

A

Olfactory receptor cells have long, thin apical dendrites that extend to the outermost layer of the epithelium (mucosal surface). At this surface, multiple cilia emerge from the dendritic knob and extend along the mucosal surface. On the other end of the bipolar olfactory receptor cell, a thin and unmyelinated axon runs through small holes in the skull to the olfactory bulb.

46
Q

How many types of olfactory receptors does an olfactory neuron express?

A

Only one- each neuron only has receptors for one type of odorant

47
Q

How many subfamilies of olfactory receptors do we have?

A

Each receptor belongs to 1 of 4 subfamilies. Within each of these families, there’s more than 1 receptor type. We have 400 types of functional odor receptors, but 1000 total. It’s possible that in evolutionary history we used to have better smell- vision took over as the more important sense over time

48
Q

Transduction of olfactory information steps (6)

A
  1. Odorant binds metabotropic receptor
  2. G-protein activated (alpha subunit is the first messenger)
  3. Adenylyl cyclase activated and makes cAMP (2nd messenger)
  4. cAMP causes cation (calcium, sodium) channels to open- these are ligand gated ion channels, with cAMP being the ligand
  5. Voltage gated Cl channels open to further depolarize cell- Cl flows out of the cell
  6. Action potential
49
Q

Which area of the brain is the primary olfactory cortex?

A

The piriform cortex

50
Q

Piriform cortex

A

Segregation of olfactory representation into the cerebral cortex (no need to go through thalamus). It does end up going to the thalamus, but goes to the piriform cortex without going to the thalamus first

51
Q

Types of taste receptors (5)

A

salty, sour, sweet, bitter, umami

52
Q

Taste buds

A

Taste buds are located on sides of taste pores between papillae (bumps). The bumps aren’t actually taste buds- taste buds are located in between them. In each taste bud, there are clusters of taste receptor cells

53
Q

Circumvallate papillae

A

Located in the back of the tongue

54
Q

Foliate papillae

A

Located along the sides

55
Q

Fungiform papillae

A

Located in the front of the tongue

56
Q

Which parts of the tongue taste which flavors?

A

It isn’t true that different parts of the tongue taste different flavors-there are 3 different types of papillae, but they can sense all 5 flavors

57
Q

How do we know that taste cells aren’t neurons?

A

Neurons are only replaced in the hippocampus and olfactory system, but taste buds are replaced every 10-14 days. They also don’t generate action potentials.

58
Q

General transduction of taste information (6 steps)

A
  1. Receptors on cilia are bound by tastants
  2. Receptor activation produces receptor potentials (like EPSPs)
  3. Taste cells do not have action potentials- instead, receptor potential (if big enough) causes neurotransmitter release onto cranial nerves (gustatory nerve)
  4. Goes to thalamus
  5. Gustotopic map in cortex- like the rest of the somatosensory cortex
59
Q

Transduction of salty taste

A

Sodium ions flow through open ion channels in the taste cell membrane, causing depolarization

60
Q

Transduction of sour taste

A

Acid sensitive potassium ion channels are blocked, preventing potassium leaving the cell and leading to depolarization. Potassium ions start open- when H binds them, they close. This means that potassium is stuck inside the cell, causing a depolarization

Behavioral Neuroscience (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions