![]() Sensations Taste, hearing, equilibrium, and vision provided by specialized receptor cells Communicate with sensory neurons across chemical synapses Gustation (taste) Equilibrium (balance) Hearingġ4 15-2 Sensory Receptors The Special Senses Special Sensory ReceptorsĪre provided by special sensory receptors Special Sensory Receptors Are located in sense organs such as the eye or ear Are protected by surrounding tissuesġ5 15-2 Sensory Receptors The Detection of Stimuli Receptor specificityĮach receptor has a characteristic sensitivity Receptive field Area is monitored by a single receptor cell The larger the receptive field, the more difficult it is to localize a stimulusġ6 Figure 15-2 Receptors and Receptive Fields.ġ7 15-2 Sensory Receptors The Interpretation of Sensory InformationĪrriving stimulus reaches cortical neurons via labeled line Takes many forms (modalities) Physical force (such as pressure) Dissolved chemical Sound Lightġ8 15-2 Sensory Receptors The Interpretation of Sensory Information The arriving information from these senses Perception Conscious awareness of a sensationġ3 15-2 Sensory Receptors Special Senses Olfaction (smell) Vision (sight) Temperature Pain Touch Pressure Vibration Proprioceptionġ2 15-2 Sensory Receptors Sensation Perception Motor neurons and pathways that control skeletal musclesġ1 15-2 Sensory Receptors General Senses Describe our sensitivity to: Specialized cells that monitor specific conditions In the body or external environment When stimulated, a receptor passes information to the CNS In the form of action potentials along the axon of a sensory neuronĨ 15-1 Sensory Information Sensory Pathwaysĭeliver somatic and visceral sensory information to their final destinations inside the CNS using: Nerves Nuclei Tractsĩ 15-1 Sensory Information Somatic Motor Portion of the Efferent Division Controls peripheral effectors Somatic Motor Commands Travel from motor centers in the brain along somatic motor pathways of: Motor nuclei Tracts Nervesġ0 15-1 Sensory Information Somatic Nervous System (SNS) Only about 1 percent of arriving sensations are relayed to the primary sensory cortex.ħ 15-1 Sensory Information Sensory Receptors Voluntary Response Motor Pathway (voluntary) Perception The voluntary response, which is not immediate, can moderate, enhance, or supplement the relatively simple involuntary reflexive response. Sensory informa- tion may be distributed to multiple nuclei and centers in the spinal cord and brain. Information processing occurs at every relay synapse. Axons of sensory neurons carry information about the type of stimulus (touch, pressure, temperature) as action potentials to the CNS. If the stimulus depolarizes the receptor cell to threshold, action potentials develop in the initial segment. Sensory Pathway Arriving stimulus Depolarization of Receptor Action Potential Generation CNS Processing Propagation A stimulus produces a graded change in the membrane potential of a receptor cell. Immediate Involuntary Response Motor Pathway (involuntary) Processing centers in the spinal cord or brain stem may direct an immediate reflex response even before sensations reach the cerebral cortex. Receptors Sensory neurons Sensory pathways Efferent Division of the Nervous System Nuclei Motor tracts Motor neuronsįigure 15-1 An Overview of Events Occurring Along the Sensory and Motor Pathways. Sensory receptors Sensory processing Conscious and subconscious motor functions Focusing on the “general senses”ĥ 15-1 Sensory Information Afferent Division of the Nervous System 15-5 Describe the components, processes, and functions of the somatic motor pathways, and the levels of information processing involved in motor control.Ĥ An Introduction to Sensory Pathways and the Somatic Nervous System Learning Outcomes 15-4 Identify the major sensory pathways, and explain how it is possible to distinguish among sensations that originate in different areas of the body. 15-3 Identify the receptors for the general senses, and describe how they function.ģ An Introduction to Sensory Pathways and the Somatic Nervous System 15-2 Explain why receptors respond to specific stimuli, and how the organization of a receptor affects its sensitivity. Learning Outcomes 15-1 Specify the components of the afferent and efferent divisions of the nervous system, and explain what is meant by the somatic nervous system. Presentation on theme: "An Introduction to Sensory Pathways and the Somatic Nervous System"- Presentation transcript:Ģ An Introduction to Sensory Pathways and the Somatic Nervous System ![]()
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