Exam 2 Study Guide

Exam 2 Study Guide - Sample Examination Questions, 15...

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Sample Examination Questions, 15 November 2007 (10-17) I assume you will have reviewed the questions at the end of each assigned chapter in the Bear et al. textbook. They are all relevant for the exam. I provide below examples of questions that may be asked on the material covered in the first seven lectures. Some exam questions will be based on these sample questions, which include my own questions as well as some taken from Bear et al. Others will be based on different end chapter questions in Bear et al.; and still others will be new. 1. How are odors transduced into neural signals? Odorant molecules reach the mucus layer and contact the cilia of olfactory cells, where it activates a G-protein called Golf protein that activates adenylyl cyclase which uses ATP to makes cAMP which binds to cation channels to allow Na+ and Ca2+ in which open Ca2+ activated chloride channels which allow Cl- to leave the cell leading to membrane depolarization of the olfactory receptor cell. This is sent up the olfactory nerve and projected to glomeruli in the olfactory bulb. Within each glomerulus the endings of about 25,000 primary olfactory axons converge and terminate on the dendrites ofoa bout 100 second-order olfactory neurons. These second order neurons make the olfactory tract that then sends the information to the olfactory cortex. Conscious perceptions of smell may go to othe olfactory tubercle to the medial dorsal nucleus of the thalamus to the orbitofrontal cortex. Strength of a smell usually fades because of adaption of the response. 2. How are signals from different types of odorant receptors represented in the olfactory bulb? 3. What are the five main dimensions of taste sensation? How do they depend on the properties of gustatory receptors? Sour, Sweet, Bitter, Salty, Umami Three types of papillae which are taste-sensitive structure. Vallate papillae, foliate papillae, and fungiform papillae. Deep within the papillae are taste buds which are a cluster of taste (receptor) cells, gustatory afferent axons and their synapses with taste cells and basal cells. Apical ends of the taste cells extend into the taste pore, the site where chemicals dissolved in saliva can interact directly with taste cells. Salt and sour have amiloride sensitive sodium channels (voltage gated) that lead to cation influx to send NTs. Bitter, sweet and umami are ionotropic which lead to activate phopholipase C which increase the synthesis of IP3 which then triggers release of Ca2+ which open voltage gated cation channels which triggers release of NTs. PKD2L1 – sour receptor the demarcates sour-sensince TRCs T1R1+T1R3 – Umami T1R2+T1R3 – Sweet T2R’s – Bitter Pathway: From taste buds to primary gustatory axons which all send into the gustatory nucleus, then diverge. Go to the ventral posterior medial nucleus (VPM) then go to the primary gustatory cortex. 4. Diagram and explain the retinal circuitry that could produce an on-center, off-surround
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Exam 2 Study Guide - Sample Examination Questions, 15...

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