Lab 6: Taste, Smell, Hearing and Vestibular Function

Question 1

adaption of taste

Answer 1

no sour adaption -> ion channels can’t be depleted
sweet becomes less intense -> GPCRs -> more activation leads to depletion of 2nd messengers -> less signals -> perceived as less intense

Question 2

mixture supression

Answer 2

when mix of sweet and sour tastes less sour than just the sour solution bc both signals to CNS, sweet signals prioritised (survival)

Question 3

mixed solution after sweet adaption

Answer 3

2nd messengers depleted -> less sweet signals -> tastes more sour

Question 4

warm ice cream

Answer 4

• smells stronger since better diffusion of particles in air
• tastes sweeter as TRP channels are temp sensitive -> more activation when warm than when cold

Question 5

retronasal olfaction, nose clips

Answer 5

food particles bind to olfactory receptors
when nose is plugged -> less flavour since less activation of olfactory receptors

Question 6

compensated vs uncompensated audiogram

Answer 6

compensated = pop ave at 0 (+ve = worse than average hearing, -ve = better than average) (straight line)
uncompensated = pop ave against absolute values of intensity and frequency (U shaped line less sensitive at high and low frequencies)

Question 7

impedance matching

Answer 7

amplification of sound waves from air to fluid (fluid has more impedance)

Question 8

how is pitch and volume of sound encoded

Answer 8

frequency/pitch: where on basilar membranecells are activated (apical end (furthest away) = wide and floppy = low pitch, basal end (closest) = stiff and narrow = high pitch)

Question 9

angular acceleration/sense of spinning

Answer 9

fluid in semicircular canals has inertia -> displaced when angular acc in plane of canal -> bending of cupula -> displacement of hair cells -> change in AP firing -> sense of rotation

Question 10

nystagmus after spinning chair

Answer 10

inertia of endolyth gives vestibular signal that we are still spinning -> fed to visual system -> eye movements to keep up with perceived motion, attempting to keep visual world in focus