Chapter 11 Notes - CHAPTER ELEVEN NEURAL TISSUE The Nervous...

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CHAPTER ELEVEN: NEURAL TISSUEThe Nervous SystemoCentral nervous system: consists of the brain and spinal cord; is responsible for integrating, processing, and coordinating sensory data and motor commandsoPeripheral nervous system: includes all the neural tissue outside the CNS1.Receptorsare sensory structures that detect changes in the internal or external environmentSomatic sensory receptors: position, touch, pressure, pain, and temperature sensationsVisceral sensory receptors: monitor internal organsSpecial sensory receptors: smell, taste, vision, balance, hearing2.The sensory division of the PNSbrings information to the CNS from receptors in peripheral tissues and organs3.Information processing includes the integration and distribution of information in the CNS4.The motor divisionof the PNS carries motor commands from the CNS to peripheral tissues and systemsSomatic nervous system: controls skeletal muscle contractionsAutonomic nervous system: regulates smooth muscle, cardiac muscle, glands, and adipose tissue5.Effectors are target organs whose activities change in response to neural commandsNeuronsoDendrites – contain dendritic spines, where most CNS information is receivedoAxonAxon hillock: the origin of the axon from the cell bodyInitial segment: distally adjacent to the axon hillock, where the action potential is initiatedAxolemma: a specialized portion of the plasma membrane that surrounds the cytoplasmof the axonAxoplasm:contains organelles such as neurofibrils, neurotubules, small vesicles, lysosomes, mitochondria, and various enzymesoCell bodyPage 1of 6
Perikaryon: the cytoplasm surrounding the nucleus that contains organelles that provideenergy and synthesize the chemical neurotransmitters that are important in cell-to-cell communication; contains neurofilaments and neurofibrilsNeurofibrils: bundles of neurofilaments that extend into the dendrites and axon, providing internal supportoTelodendria – a series of fine extensions from the main axon trunk that end at axon terminalsoAxoplasmic transport: a process by which materials such as enzymes and lysosomes travel the length of the axon along neurotubulesoSynapse: a specialized site where the neuron communicates with another cellsIncludes a presynaptic cell and a postsynaptic cellCommunication between cells most commonly involves the release of chemicals called neurotransmittersinto the synaptic clefNeurotransmitters are packaged in synaptic vesiclesThe synaptic clef separates the presynaptic membrane, where neurotransmitters are released, from the postsynaptic membrane, which has receptors for neurotransmittersA presynaptic cell is almost always a neuron, and the postsynaptic cell can be another type of cellSynapses with another neuronNeuromuscular junctionsNeuroglandular synapsesCollateral branches: side branches along a neuron that enables a single neuron to

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