生理学09 感觉器官的功能幻灯片.pptVIP

第五节、嗅觉和味觉的形成（自学） 2004年诺贝尔生理学/医学奖 美国科学家理查德·阿克塞尔和琳达·巴克 研究人体气味受体和嗅觉系统组织方式 Olfactory Nerve Olfactory Epithelium [cilia， not microvilli， with Na channels] [mucus] [synaptic connections] [2nd order neuron] Cranial Nerve I Brain [1st order neuron] [axons] [neuroepithelial cells] Dissolved molecules. 鼻腔内嗅觉感受器Olfactory receptors of the nose [Taste =~ 80% of Smell] 味蕾的结构和功能 Microvilli contain receptors for various taste-producing Molecules.] [ bitter Intracell. Ca sour- acid H- channels Salty， Na- channels sweet， close K-channels umami [in rear wall of pharynx] [mitosis] （40-100 cells） receptor cell=neuroepithelial cell NEW PHYSIOLOGICAL IDEA: Neuroepithelial Cells To cranial N.VII， Facial； [synaptic vesicles] IX， G’pharyn X，Vagus [Fig. 15..2] 味觉传导通路Gustatory Pathway 复习思考题 Receptor(sensor); sensory organ; pupil reflex; visual acuity; dark adaptation; visual field; blind spot; vestibular response; nystagmus 感受器的一般生理特征。 视网膜如何感受明暗和色彩？ 眼的调节方式及其生理意义。 简述视觉的产生过程。 简述听觉的产生过程。 * In the cilia， odorants are detected and transduced into a generator potential through a well defined second–messenger system. Cyclic AMP produced in the cilia opens a cation–permeable cyclic–nucleotide–gated channel， which depolarizes the membrane from its normal resting level （–60 mV） to as much as –40 mV. An unusual calcium–dependent chloride channel is also activated， and because the intracellular concentration of chloride is high， the outward flow of chloride ions adds to the depolarization. The sensory generator potential then spreads passively to the somatic membrane， where it activates calcium， sodium and potassium channels to produce an action potential. A spike train of action potentials propagates down the axon to the synaptic terminals in the olfactory bulb. It is the structure of this spike train that Kawai and colleagues showed is modulated by adrenaline through the action of the second messenger cAMP.