nervous system - Nervous system Neural tissue is...

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Nervous system Neural tissue is specialized for TRANSMISSION OF ELECTRICAL IMPULSES… this is the way that messages are transmitted and received in your body. In a very general sense, the job of the nervous system is to receive SENSORY IN (could be from outside, or inside your body); and transmit MOTOR OUT (response to sensory). In between, there is much coordination and integration… but moving information in and out is the basic job. Neurons – generate electrical impulses and thus communicate Neuroglia – support cells for neurons – separate and protect, supportive framework, regulate composition of interstitial fluid. (Many more neuroglia than neurons) Many ways to divide the nervous system: 1. Central vs. peripheral Central nervous system – spinal cord and brain. Integrating, processing, coordinating sensory data and motor commands. Sensory – information in; motor – response out. Peripheral nervous system - neural tissue outside CNS – delivers sensory info and carries motor commands to peripheral tissues. What we think of as “nerves” are bundles of axons carrying information into and out of CNS. 2. Sensory vs. motor Sensory is moving information into the CNS (afferent) Motor is moving information out of the CNS (efferent) Sensory can also be divided into: General senses: pain, temperature, touch, pressure, vibration, proprioception Some of this is relayed to CNS and we are conscious of it (perception), some is not. General sensory information is relayed to the general sensory area of the brain. Special senses: olfaction, vision, taste, equilibrium, hearing. Receptors for these are located in sensory organs, and info is provided to specific sensory cortexes… thus they are special, in that they have their own special place to be sensed. 3. Somatic (voluntary) vs. autonomic (involuntary) Different parts of your body are run by different divisions of the nervous system… anything voluntary (skeletal muscle) is somatic; involuntary (heart, breathing, gland secretion, etc) is autonomic. Autonomic can also be divided into: Sympathetic: increase HR, breathing, dilate pupils… “fight or flight” Parasympathetic: decrease HR, breathing, increase digestion and urine production… “rest and digest” Structure of a neuron: Cell body: Large round nucleus. Dendrites: slender processes out from cell body – highly branched – information comes into cell body from here. Axon – long process that propagates electrical impulses known as action potentials.
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Synapse: space between neurons. Neurotransmitters – chemicals that carry messages across synapse in synaptic vesicles. Thus, electrical signal must be converted to a chemical signal, then back to an electrical signal. Neuroglia:
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nervous system - Nervous system Neural tissue is...

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