QUIZ 3 Taste and Olfaction STUDY GUIDE Will consist of multiple choice fill in the blank true false and short answer questions NOTE If a question asks What is you must be able to define that term not describe what happened in the lab Gustation Know the types of taste receptors 4 or 5 primary tastes Bitter Sweet Salty Sour Umami How is transduction initiated for each of the different types of receptors Salt and Sour both tastants are small charged molecules and use ionotropic receptors Salt Na enters thru channel on microvilli depolarization allows Na and Ca2 in thru voltage gated channels neurotransmitters release AP in taste nerve Sour Acids in water have a free proton hydrogen H blocks K channel K can t leave cell cell depolarization Na and Ca2 into cell thru V G channels neurotransmitters release AP in taste nerve Bitter Sweet Umami Tastants stimulated metabotropic receptors tastant molecule binds to metabotropic receptor on microcell G protein activated 2nd messenger made Ca2 let into cell from internal store Na into cell as well neurotransmitters release AP in taste nerve Be able to write out taste pathway no abbreviations Taste info carried by 3 cranial nerves Chorda Tympani branch of facial nerve CNVII Glossopharyngeal CNIX and Vagus CNX Cranial nerves Nucleus of the solitary tract NST in medulla Thalamus Insular Cortex Types of papillae characteristics of each Fungiform mushroom shaped found on apex and sides of the tongue contains 6 taste buds per papillae Foliate taste rear sides of tongue where it attaches look like folds taste buds buried in the folds Filiform cone or V shaped mostly on rear of tongue contain no taste receptors purely mechanical and structural most numerous different shapes in different species Circumvallate taste large and circular like islands with moats taste buds buried in the moats Cranial nerves associated with tongue taste tactile chemical Vagus Nerve CNX back of tongue Glosspharyngeal CNXI middle of tongue Chorda Tympani CNVII front of tongue Trigeminal Nerve CNV for cutaneous info touch temp pain What physiological anatomical quality makes some people super tasters Super tasters TT have denser population of fungiform papillae can taste PROP Olfaction What type of receptors do odorants activate I e how is transduction begun in the cell Olfactory receptors Odorant molecules act in the mucus layer of the epithelium olfactory molecules bind to G coupled protein receptors on the cilia of the OSNs transduction occurs an AP the axons of the OSNs CNI travel thru the cribriform plate and synapse onto glomeruli within the olfactory bulb the axons of the mitral converge to form the Lateral Olfactory Tract which goes from the olfactory bulb to the limbic system What are the properties of odorant molecules Volatile vaporable able to float in the air Hydrophobic water avoiding Small mass molecular weight 294 kDa Olfactory sensory neurons o What brain regions do they project to Primary Olfactory Cortex Pyriform Cortex Amygdala Septal Nuclei Hippocampus Entorhinal Cortex o Where do they synapse Synapse onto glomeruli along with the dendrites of mitral cells and tufted cells directly to amygdala o HOW do they work How are they activated how do they transmit signals where does the signal go afterward OSNs have cilia that protrude into mucus cilia have receptors on their tips these receptors detect odorants once the odorant has been bound to a matching receptor a neural signal is produced that travels along the receptor axon thru the cribriform plate to the glomeruli of mitral cells which lie in the olfactory bulb these cells produce a signal which is modified until it s sent down the olfactory nerve tract to several brain areas Be able to define the two different types of olfaction Orthonasal olfaction inhaling odorant is carried through the air inhaled through the nostrils and then to nasal receptors Retronasal Olfaction breathing in out through your mouth odorant enters through mouth is then diffused though the nasopharynx to nasal receptors and exits though the nostrils Know the types of cells in the olfactory epithelium and olfactory bulb Olfactory sensory neurons OSNs 8 20 cilia per OSN cilia have olfactory receptors on their tips Supporting cells Basal cells What cranial nerve is associated with olfaction What is it made up of I e axons of which cells from where to where Olfactory nerve CNI Axons of the mitral cells converge to form the lateral olfactory tract which goes from the olfactory bulb to the limbic system What is flavor Flavor is metasensation created by brain based on taste and smell chew and swallow food makes molecules released into air outside mouth and forced up behind palate in nasal cavity stimulate olfactory receptors retronasal olfactory sensations Know the functions of and be able to define the following terms o Turbinates ridges that add turbulence to incoming air to send some thru the olfactory cleft and onto the olfactory epithelium o Mitral cells axons o Cribriform plate bony structure that separates the nose from the brain axons travel through it o Glomeruli cluters dendrites of mitral cells
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