Ch9&10 Nervous System

Ch9&10 Nervous System - 1 The Nervous System The...

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Unformatted text preview: 1 The Nervous System The Nervous System Chapters 9 & 10 Chapters 9 & 10 Nervous System (NS) Nervous System (NS) Functions of the NS: s Sensory input : gathering information s Integration: processes & interprets sensory input, and decides if action is needed s Motor output: response to integrated stimuli c effectors s NS is classified by structure and function Structural Classification Structural Classification Functional Classification of PNS Functional Classification of PNS Nervous Tissue: Neurons Nervous Tissue: Neurons s Functional cells of the NS s Specialized to transmit stimuli s Cell body: nucleus & cell organelles s Cytoplasmic extensions from the cell body form s Dendrites s Axons s Typically short, highly branched & unmyelinated s Myelin : a white fatty material surrounding most axons s Conduct impulses towards the cell body s Receptors of stimuli s Surface specialized for contact with other neurons Neuron Anatomy: Dendrites Neuron Anatomy: Dendrites 2 s Long, thin single fibers s Conduct impulses away from the cell body s End in axon terminals s Most axons are myelinated s Synaptic end bulbs contain vesicles with neurotransmitters s Nerve impulses may be delivered to another neuron, muscle or gland Neuron Anatomy: Axons Neuron Anatomy: Axons Neuroglia (Glial Cells) Neuroglia (Glial Cells) s NS support cells s protect the nervous tissue (i.e. neurons) s aid in cell repair s act as phagocytes s regulate the composition of interstitial fluids s Appear throughout the CNS and PNS s Continue to multiply throughout life s most NS tumors are tumors of neuroglial tissue Neuroglia Neuroglia Astrocytes s Star-shaped cells s Attach to brain capillaries s Form a barrier between capillaries & neurons s part of the blood-brain barrier s Regulate nutrients & wastes transport to & from neurons Neuroglia Neuroglia Microglia s Small spider-like phagocytes s Near blood vessels Ependymal cells s Line fluid-filled cavities of the brain & spinal cord s Circulate within the cerebrospinal fluid (CSP) s Ciliated Neuroglia Neuroglia s Oligodendrocytes: s most common glial cell s form myelin sheath around nerve fibers in the CNS s Schwann cells : form myelin sheath around nerve fibers in the PNS s Satellite cells : protect neuron cell bodies in PNS s Insulates and protects the axons s Myelinated axons are called white fibers s Schwann cells (in the PNS) wrap around the axon like a jelly roll & deposit layers of myelin The Myelin Sheath The Myelin Sheath 3 Nodes of Ranvier s Gaps in myelin sheath along the axon s Speed the conduction of nerve impulses Neurilemma s Outermost membrane of schwann cells s Important role in the regeneration of damaged nervous tissue in the PNS s Not present in oligodendrocytes (in CNS), thus damage to CNS cells are considered permanent The Myelin Sheath The Myelin Sheath Types of Neurons Types of Neurons Interneuron Sensory Neuron Motor Neuron Types of Neurons Types of Neurons Sensory/ Afferent neurons s carry impulses from the sensory...
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This note was uploaded on 05/04/2008 for the course HP 320 taught by Professor Islam during the Spring '08 term at USC.

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Ch9&10 Nervous System - 1 The Nervous System The...

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