Neurons, Synapses, and Signalling

Neurons, Synapses, and Signalling - Neurons, Synapses, &...

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Neurons, Synapses, & Signalling Page -1- NEURONS, SYNAPSES, AND SIGNALLING INFORMATION PROCESSING y nervous systems have 2 main divisions (see fig. 48.3). .. y central nervous system (CNS). .. responsible for integration; the brain and spinal cord in vertebrates y peripheral nervous system (PNS). .. responsible for sensory input to the CNS and motor output from CNS y nervous systems have 3 overlapping functions (see fig. 48.3). .. y sensory input. .. signals from sensory receptors are sent via PNS to integration centres of the CNS y integration. .. signals from sensory receptors are interpreted by the CNS and an appropriate response is formulated y motor output. .. signals are sent from the CNS to effector cells via the PNS (these cells actually perform the response) NEURONS ARE THE FUNCTIONAL UNITS OF NERVOUS SYSTEMS y 2 main types of cells occur in vertebrate nervous systems. .. y neurons. .. conduct chemical & electrical signals y neuroglia ( supporting cells ; also called glial cells )... y involved in structural reinforcement and protection y some provide insulation while other assist with metabolic functions y glia vastly outnumber neurons (10-50x) fig. 48.3 Information processing in the nervous system.
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Page -2- GENERAL STRUCTURE OF NEURONS y cell body. .. (see fig. 48.4) y contains the nucleus and most of the cytoplasm y ganglia are clusters of cell bodies from many neurons y 2 types of cell “processes” (specialized extensions of the plasma membrane). .. y dendrites. .. short, numerous, branched y receive signals from other neurons and convey those signals to the cell body y axons. .. long processes y usually 1 or 2 per neuron y have terminal branches that end in synaptic knobs y conduct signals away from the cell body, transmitting them to other cells y many vertebrate axons of the PNS are enclosed by Schwann cells and may have a myelin sheath y axon hillock. .. fig. 48.4 Neuron structure y at the branched ends of an axon synaptic terminals are found that form a specialized junction called a synapse y information is transmitted from the presynaptic cell to the postsynaptic cell at one or more synapses y many synapses employ chemical messengers, neurotransmitters , secreted by the presynaptic cell. .. this occurs at
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This note was uploaded on 01/15/2011 for the course BIOL 190B taught by Professor Dr.davidcreasey during the Spring '10 term at University of Victoria.

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Neurons, Synapses, and Signalling - Neurons, Synapses, &...

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