HMB200H1 Chapter Notes - Chapter 8: Aroma Compound, Antibody, Glycosaminoglycan
Document Summary
Taste is mostly tongue, but also: pharynx, epiglottis, palate. Fungiform small at top/edges, large at back. Taste bud = taste cells and gustatory afferent axons + synapses with different taste and basal cells. Sourness -> h+ enters through amilonde sensitive na+ channels. Saltiness -> na+ enters amil-channel for depolarization. Sweetness -> receptor up of t1r2 + t1r3 (only one kind) Umami -> receptors made of t1r1 + r1r3 (only one kind) Bitterness -> 30 kinds, all made up of t2r. Facial nerve (vii) -> anterior 2/3 of tongue + palate. Glossopharyngeal (ix) nerve -> posterior 1/3 of tongue. Afferents from tongue and epiglottis left gustatory nucleus (in medulla) left ventral posterior medial nucleus (vpm) of thalamus -> primary gustatory cortex (cerebral cortex) (postcentral gyrus and insular cortex) Labelled line hypothesis: specific receptors, axons, cells for each taste, broad tuning. Population coding -> responses of large, not small (fine) number of broadly tuned neurons, specify stimulus properties.
