4) Hearing, Smell, Taste Flashcards
Sound
A vibration or mechanical energy travelling through a medium
Produced by mechanical disturbance (vibrating molecules)
describe the binaural vs monaural cues
cues that detect source of sound
binaural
- most used, compare time & loudness difference between ears
monaural
- clear vs muffled sounds
Pitch
frequency of wave (hertz)
Age matters! Younger people more sensitive to higher pitches
Loudness
amplitude of wave (dB)
louder = more mechanical disturbance
Timbre
quality / complexity of a sound
evident in diff music instruments
describe the structure of our ear
- Outer
- pinna
- ear canal
Eardrum
- Middle
- ossicles - Inner
- cochlea
(organ of corti + basilar membrane)
Outer Ear
funnels sound waves into eardrum
Pinna: cartilage we see
Ear canal
Middle Ear
Ossicles: tiny bones called malleus, incus, stapes
(hammer, anvil, stirrup)
Vibrates at frequency of sound wave to transmit from eardrum -> inner ear
Inner Ear
Cochlea converts vibrations -> neural activity
= transduction
- bony spiral w/ fluid inside
- contains organ of corti & basilar membrane
Organ of Corti
in cochlea
tissue containing hair cells necessary for hearing
Basilar membrane
membrane in cochlea supporting organ of corti + hair cells
How does transduction happen for hearing?
in hair cells in cochlea
convert info -> action potentals
Hair cells have cilia (hair-like stuff) sticking in fluid of cochlea
Pressure from sound deflect cilia, excites hair cells -> auditory nerve
What are the theories of pitch perception?
Place
Frequency
Volley
Place theory
Specific place along basilar membrane & auditory cortex matches a tone with specific pitch
Base = more sensitive to high pitch
Only accounts for HIGH PITCHES
Frequency theory
Rate that neurons fire reproduces pitch
0 - 100Hz (maximal firing rate)
Volley theory
Variation of frequency theory
Sets of neurons fire slightly out of sync to reach higher frequencies
100 - 5000 Hz
Music + hearing
We’re sensitive to the arrangement of tones into melodies when listening to music
React differently, making diff brain regions active, etc
Explain the reasons why we cannot hear
Genetics, disease, injury, ageing, exposure to loud noise
Conductive deafness
- malfunctioning eardrum or ossicles
Nerve deafness
- damaged auditory nerve
Noise-induced hearing
- loud sounds that last a long time / are repeated / are super loud can damage hair cells
- Accompanied by tinnitus (ringing, roaring)
Aging
- lose hearing ability especially for higher pitch
- loss of sensory cells
- degeneration of auditory nerve
What is the most important function of smell and taste?
to sample food before we swallow, keeps us alive
Olfaction
Our sense of smell
More advanced, thousands of diff types of smells
Olfactory neurons contain receptors that recognizes odors like lock & key
Plays strong role in sexual behavior
Siblings can recognize each other based on odor
Odors & Pheromones
Airborne chemicals that interact with receptors in nose
Pheromones are odorless chemicals that are social signals, alters sexual behavior
Gustation
Our sense of taste
5 basic tastes: sweet, salty, sour, bitter, umami (savory)
Taste perception is biased strongly by smell!
Emotional disorders can distort taste perception
Tongue taste map
Myth!
Every location on tongue is slightly sensitive to all tastes, even if some are more concentrated in certain areas
Taste buds
Sense receptors in tongue that respond to tastes
Umami taste buds contained lots of glutamate
Everyone has diff number of taste buds
Supertasters have lots
Tasting fat
As soon as it enters mouth, starts to affect body’s metabolism of fat
Cannot smell fat, has to touch tongue
Shows evidence fat is a taste!
Describe how we perceive smell & taste
Smell sense receptors in nose
-> olfactory cortex & parts of limbic system
Taste buds
-> gustatory & somatosensory cortex (cuz food has texture too) & parts of limbic system
Frontal cortex:
site of convergence for smell & taste
Parts of limbic system:
help us see if its pleasant or disgusting
