Lecture 11: Smell and Hearing Flashcards
olfaction
specialized for identifying special molecules called odorants
what kind of receptors detects smell?
metabotropic g protein-coupled receptors
how do receptors detect smell?
Metabotropic g protein-coupled receptors transduce ions into a change in membrane potential
how many odorant receptors are there per odorant molecule?
1
are odorant molecules lipid soluble?
yes
are odorant molecules organic (made from life)?
yes
Olfactory epithelium
the tissue of the nasal sinus that sits underneath the skull (the cribriform plate) and contains olfactory receptor cells
how many types of receptor proteins does each olfactory cell express?
1
Glomeruli
located in the olfactory bulb. Where olfactory receptor cells synapse, which in turn sends axons to the brain
each glomerulus processes information about ____ types of olfactory receptor cells
1
what process allows us to recognize smells?
combinational processing
how many smells can humans recognize
tens of thousands
how is smell perception developed?
through learned assocaitions
is smell innate?
no
where does olfactory information go?
to the primary olfactory cortex in the temporal lobe, then to the amygdala
sound waves
fluctuations in air pressure that are caused by the molecules of air surrounding a vibrating object condensing and rarefying (pulling apart)
how fast do sound waves travel?
~700 MPH
what length of soundwaves can humans detect?
1.7 cm-17 m
what sound wave frequencies can humans detect?
20-20,000 times per second
3 dimensions of sound
loudness, pitch, and timbre
loudness
corresponds to the amplitude or intensity of the molecular vibrations
how is loudness determined?
by the total number of hair cells that are active and their overall activity levels
pitch
corresponds to the frequency of the molecular vibrations
how is pitch measured?
in hertz (Hz) or cycles per second
what is another word for pitch
tone
how is pitch determined?
place coding for moderate to high frequencies
rate coding for low frequencies
timbre
corresponds to the complexity of the sound
why do we use timbre
to determine the source of sound waves
how is timbre determined
Perceived by assessing the precise mixture of hair cells that are active throughout the entire cochlea
pinna
outer ear; receives sound from the external environment
typanic membrane
vibrates in response to sound waves and transfers them to the middle ear
middle ear
composed of three ossicles (small bones)
three ossicles
malleus, incus, stapes
oval windows
receives the vibrations from the ossicles and transmits them to the cochlea
cochlea
inner ear; a long, fluid-filled, coiled tube-like structure that contains sensory neurons. divided into three longitudinal divisions
three longitudinal divisions of the cochlea
Scala vestibuli
Scala media
Scala tympani