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Unformatted text preview: Chapter 48: Nervous System 18/02/2008 18:40:00 1. Name the three stages in the processing of information by the nervous systems. Sensory input o Sensory neuron-transmit information from sensors that detect external stimuli (light, sounds, touch, heat , smell, and taste) and internal conditions (blood pressure, blood CO2 level, and muscle tension) Integration o Interneuron-information from sensory neuron is sent to CNS where sensory input is integrated (analyze and interpret) o Takes into account the immediate context as well as what happened in the past Motor output o Motor neurons- where motor output leaves the CNS which communicates with effector cells (muscle cells or endocrine cells) 2. Distinguish among sensory neurons, interneurons, and motor neurons. Sensory neuron: a nerve cell that receives information from the internal and external environments and transmits the signals to the central nervous system Interneuron: an association neuron; a nerve cell within the central nervous system that forms synapses with sensory and motor neurons and integrates sensory input and motor output Motor neuron: a nerve cell that transmit signals from the brain or spinal cord to muscles or glands 3. List and describe the major parts of a neuron and explain the function of each. Dendrite: highly branched extensions that receive signals from other neurons; one of usually numerous, short, highly branched processes of a neuron that convey nerve impulses toward the cell body Axons: a typically long extension, or process from a neuron that carries nerve impulses away from the cell body toward target cells Axon hillock: the conical region of a neurons axon where it joins the cell body; typically the region where nerve signals are generated Myelin sheath: in a neuron, an insulating coat of cell membrane from Schwann cells that is interrupted by nodes of Ranvier, where salutatory conduction occurs Synaptic terminal: a bulb at the end of an axon in which neurotransmitter molecules are stored and released Synapse: the locus where one neuron communicates with another neuron in a neural pathway; a narrow gap between a synaptic terminal of an axon and a signal-receiving portion of another neuron or effector cell Presynaptic cell: the transmitting cell at a synapse Postsynaptic cell: the target cell at a synapse Neurotransmitter: a chemical messenger released from the synaptic terminal of a neuron at a chemical synapse that diffuses across the synaptic cleft and binds to and stimulates the postsynaptic cell 4. Describe the function of astrocytes, radial glia, oligodendroctues and Schwann cells....
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- Winter '08