Week 6 (How do we hear, taste, and smell?) Flashcards

1
Q

What are the properties of sound

A

-Frequency & Pitch
-Amplitude & Loudness
-Complexity & Timbre

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2
Q

What is Frequency & Pitch

A

Rate of vibration n cycles per second (Hertz, Hz)

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3
Q

What is Amplitude & Loudness

A

Intensity of sound (Decibels, Db)

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4
Q

What is Complexity & Timbre

A

Complexity determines Timbre, (e.g. difference between violin and flute)

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5
Q

What are the three sections of the ear?

A

Outer ear, Middle ear, Inner ear

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6
Q

What are the components of the outer ear?

A

Pinnae: Funnel-like structure channels sound into ear.

Ear canal: Narrowing amplifies sound waves toward membrane (tympanic membrane)

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7
Q

What are the components of the middle ear?

A

Osssicles:
-Malleus (Hammer)
-Incus (Anvil)
Stapes (Stirrup)

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8
Q

What are the components of the inner ear?

A

Cochlea:
-Converts vibrational energy into waves of fluid
-The auditory part of the vestibulocochlear nerve

Inner ear includes vestibular apparatus.

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9
Q

Structure and function of the Cochlea

A

-Coiled structure, bony exterior, hollow compartments, filled with fluid.
-Vibrations from the ossicles to oval window membrane sends waves through fluid filled cochlea.

-Vibration is transmitted to organ of court via basilar membrane (structures in cochlea)
-Movement in sensory hair cells transduce sound waves into neural activity, which is sent along auditory nerve to the brain.

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10
Q

Structure and function of the tonotopic basilar membrane.

A

The basilar membrane vibrates when stapes moves the fluids of the inner ear. Different sound wave frequencies cause peak pending f the membrane at different points along its length.

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11
Q

What does the Organ of Corti

A

Sends vibrations to auditory nerve.

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12
Q

What is the auditory pathway to the brain?

A

-Ear (cochlea)
-Cochlear nuclei (brainstem)
-Superior olive (brainstem)
-Inferior Colliculi (midbrain)
-Medial geniculate nucleus (thalamus)
-Auditory cortex (Temporal cortex

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13
Q

Where are the primary and secondary auditory cortex located?

A

Primary:
Located in the temporal lobe, within the Heschl’s gyrus, within the Sylvia fissure, tonotopic.

Secondary:
-Surrounds primary auditory cortex,

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14
Q

What allows us to hear pitch

A

Tonotopic organisation in the basilar membrane.

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15
Q

What allows us to hear loudness

A

Louder sounds produce larger pressure changes, produces more intense basilar vibration.

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16
Q

How do we detect location

A

-Difference in timing in each ear
-Relative loudness

Detected by nuclei in the brainstem that receive input from both left and right ventral cochlear nuclei.

-Superior olive (medial part) neurons respond to difference in arrival time between each ear.

-Superior olive (lateral part) and trapezoid body neurons respond to differences in loudness.

17
Q

Two types of deafness

A

Conduction deafness
-Pathology of the outer/middle ear: prevent vibrations reaching cochlear

Sensorineural deafness/ hearing loss
-Originate from cochlear or nerve lesions
-Cochlear losses most common

18
Q

Damage to auditory cortex

A

Left primary auditory cortex damage:
-Deficit in differentiating speech sounds

Right primary auditory cortex damage
-Deficit in discriminating musical sounds

Bilateral auditory cortex damage
-Agnosia for sound (everything sounds the same)

19
Q

Fancy word for smell

A

Olfaction

20
Q

Olfactory segment

A

-Along the roof of the nasal cavity
-Lined with the olfactory epithelium, which contains receptors for smell.

21
Q

Olfactory receptors

A

Each olfactory receptor has a short thick dendrite, ending in 10 to 20 cilia, that projects into a mucous layer (olfactory mucosa)
-Chemicals in air dissolve into mucosa to interact with cilia

22
Q

Olfactory bulbs

A

Receptor cells project to olfactory bulbs

Theolfactory nervesare non-myelinatedand consist of bundles of slenderfibresheldtogether by thin strips of connectivetissue; form olfactory cranial nerve

Receptors form synapses with dendrites of mitral cells at glomeruli
Mitral cells send axons from olfactory bulb to a broad range of forebrain areas

23
Q

Path from olfactory bulbs to the brain.

A

Mitral cells send axons from olfactory bulb to a broad range of forebrain areas
Amygdala & pyriform cortex have no connection through thalamus
Orbitofrontal cortex (role in emo & social behaviours) has thalamic connection

24
Q

Abnormalities of olfaction

A

Anosmia (absence of the sense of smell)
-Can be anosmic for certain odours
-Can be temporary or permanent

Hyposmia (diminished olfactory sensitivity)
-Hyposmia might be very early sign of Parkinson’s disease

Dyosmia (distorted sense of smells)
-Misinterpreted smells of hallucination of smells

25
Q

The tongue

A

Covered in papillae and taste buds

26
Q

What are the different taste senses?

A

Sweet, salty, sour, bitter, umami

27
Q

Taste pathways to the brain

A

Pathway one:
-Through posterior medulla to ventroposterior medial nucleus of thalamus

Then through two sub pathways

-one to primary somatosensory cortex (tactile information )
-one to gustatory cortex of insult (flavour)

Pathway two:
-projects through pons to hypothalamus & amygdala
Hypothesised to play a role in feeding behaviour.