Understanding Sensory Systems: Balance, Taste, and Smell
Explore the intricate workings of human sensory systems, focusing on balance through the vestibular system, and insights into taste and smell. This lecture covers the interconnectedness of sensory modalities, illustrating how vision, proprioception, and vestibular inputs work together to maintain balance. Additionally, delve into the fascinating aspects of taste perception, including sweet, sour, and umami flavors, and the complexity of olfactory receptors involved in smell. Join practical experiments and discover how these systems shape our experiences.
Understanding Sensory Systems: Balance, Taste, and Smell
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Presentation Transcript
Extra Credit Experiments To volunteer go to www.tatalab.ca Click on a blue time in the calendar to sign up for that appointment time
Exam 1 • M,T,W,Th of next week • Covers everything up to and including hearing (i.e. the previous lecture)
A quick peek at all the other sensory systems we don’t have time to consider Touch, Taste, Smell, Proprioception, Thermoception and Balance
How do we Stay Balanced? The Vestibular System
Vestibular System (Balance) Head accelerates this way Fluid goes this way Cupula gets pushed
Vestibular System (Balance) Fluid goes this way Head accelerates this way Cupula gets pushed
Vestibular System (Balance) • movement of the cupula is detected by hair cells • hair cells in the vestibular system are more sensitive than hair cells on the basilar membrane!
Vestibular, Visual, and Proprioceptive Systems Work Together • Balance is a multimodal sense and is an example of cross-modal integration • Try standing on one foot with your eyes closed!
Fun Facts about The Vestibular System • Seasickness arises when the vestibular system and the visual system send conflicting information
Fun Facts about The Vestibular System • Seasickness arises when the vestibular system and the visual system send conflicting information • People can be knocked down by moving walls!
Fun Facts about The Vestibular System • Seasickness arises when the vestibular system and the visual system send conflicting information • People can be knocked down by moving walls! • Alcohol causes the spins by (among other things) changing the density of the fluid in the semicircular canals
Sensory Systems: • Touch, temperature, taste, smell
Touch receptors send signals to the somatosensory cortex via long axons in the spinal cord • Signals are sent to the opposite (contralateral) side of the brain
The Homunculus • Wilder Penfield - Montreal Neurological Institue - 1940’s • Found somatotopic map by stimulating brain during surgery
Thermoception • Two classes of thermoreceptors: warm and cold
Taste (Gustation) Taste buds contain chemical receptors
Taste What are the various “tastes”?
Taste • Multi-dimensional scaling reveals several “varieties” of tastes: • sweet • salt • bitter • sour • umami (MSG) - possibly a protein receptor • there may also be a lipid (fat) receptor
Smell • Olfactory bulb receives input from olfactory receptors which contact mucus in nasal cavity
Smell • There are thousands of different receptors for different kinds of molecules
Smell • Olfactory receptors use a “lock-and-key” mechanism - only specific molecules will bind with a given receptor Odor Molecules Receptor
Smell • Odor recognition is excellent in humans • but odor identification (naming) is very poor • Women tend to be (slightly) better than men at naming smells
Smell • Smell is strongly influenced by “top-down” processes such as what you are expecting to smell
