Gustation lecture Neuro 3206 Lec 4

January 22, 2018 Off By admin
Question Answer
what is the retronsal olfactory sensation the sensation of an odor that is perceived when chewing and swallowing causes a release of odorant molecules in the mouth
what receptors are used for high acidity or high temperature Noiceceptors
what receptor is detects textures and viscosity of food Mechanoreceptors
how many receptor cells are on the taste bud and what is the life span of them 50-150
2 weeks
what is the part of the receptor cell that is a slender projections on the apical tips of taste receptor cells that extend into the tast bud microvilli
what is the process of the gustatory pathway info transfers to cranial nerves VII IX X–>
gustatory nucleus in medulla –>
VPM of thalamus–>
primary gustatory cortex in the insular cortex of the frontal lobe –>
2nd gustatory cortex
What is the term used to describe the loss of taste perception Ageusia
what is two features of the labeled line hypothesis off taste -individual taste receptor cells for each stimuli
-most neurons long gustatory pathway are broadly tuned
What ae 3 features of the population coding of taste -roughly labeled lines
-large # of broadly tuned neurons
– contribution of temperature and textural features of food
What is the population coding of temp and textual combination with retronasal olfaction
What are the two general categories that tastants are divided by small particles-perceive salty and sour
large chemicals- activate G-protein receptors, perceive sweet bitter umami
How is the perception of salt done? (2) 1.salt ionizes
2. Na activates sodium selective channels and Depolarize taste cell
what drug blockes salt receptors amiloride
How is the perception of sour done in the taste cell 1. caused by H+ protons found in acidic solutions
2. DP taste receptor
what family of receptors is the H+ of the sourness receptor part of? Transient Receptor potential (TRP)
What can H+ do to K+ channels H+ can bind to and block special K+ selective channels
what type of element are natural stimuli Alkaloids
How does the GCPR pathway for bitterness work(3) 1.Activates Ga protein called gustducin
2. Gustucin activates phospholipase C–> inc IP3
3. IP3 activates a DP, Na+-permeable TRP channel (TRPM5
What subtype is the GPCR for bitterness 25 T2R subtype
How are different T2R molecules responded -some respond to specific
-some are genelized that respond to many
how do salt and bitterness work with each other they inhibit each other
How does the process of perceiving sweetness done in the taste bud 1.evoked by sugar
2. receptors are GPCRs (T1R2/3) that activate same general PLC/IP3/TRPM5 pathway as described for bitter receptors
What is the term used to describe the T1R2/3 receptors heterodimers (two distinct subuntits)
what acid found in meats and cheeses gives the perception of umami glutamic acid
how does the process of perception of umami occur 1.flacouring gent forms monosodium glutamate
2.binds to glutamate receptors
3. specific brain cells in the olfactory cortex respond to umami taste
What type of receptors are used in umami GCPRs (T1R1/3) that activate PLC/IPs/TRPM5 pathway of bitterness