Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download The Nervous System and Nervous Tissue
Document related concepts
Transcript
Ch. 12 The Nervous System and Nervous Tissue Objectives • Understand how the nervous system is divided and the types of cells that are found in nervous tissue • Know the anatomy of a neuron and the structural and functional types of neurons • Understand what occurs at the synapse The Nervous System • Maintains internal coordination – Sensory information – Processing – Response • Two major subdivisions – Central (CNS) • Brain and spinal cord – Peripheral (PNS) • Nerves and ganglia Divisions of Nervous System legacy.owensboro.kctcs.edu Divisions of Nervous System • CNS – brain and spinal cord • PNS – Cranial nerves – Spinal nerves – Sensory division • Sensory information form environment to CNS – Motor division • Somatic – Impulses to skeletal muscle • Autonomic – Impulses to cardiac and smooth muscle, glands » Sympathetic » parasympathetic Neurons • Communication cells of the nervous system • Properties that allow communication – Excitability – Conductivity – Secretion • Three functional classes – Afferent (sensory) neurons – Interneurons (association neurons) – Efferent (motor) neurons Neuron Structure • Soma – control center – Chromatophilic (Nissl) bodies – Neurofibrils • Dendrites – Receptive sites – Conduct towards • Axon Hillock • Axon – Impulse generators – Conduct away mindcreators.com Synapse • Site of neuronal communication • Two types – Axodendritic – Axosomatic • Synaptic cleft – neurotransmitters catalog.nucleusinc.com Structural Classification science.howstuffworks.com Neuroglial Cells • Four types of glial cells – Astrocytes • Synapse formation – Brain derived trophic factor • Nourish • Regulation of neurotransmitters • K+ regulation – Oligodendrocytes • myelination – Microglia • Immune protection • Macrophages – Ependymal cells • Internal lining of CNS • Production of CSF • Two types of glial cells found only in PNS – Schwann cells • Myelination – Satellite cells • Provide electrical insulation around soma • Chemical regulation Myelination nature.com faculty.stcc.edu Nerves • Nerve – Collection of nerve fibers in the PNS • Nerve composed of multiple axons • Epineurium • Perineurium – Fascicles • endoneurium web.uaccb.edu Grey and White Matter of CNS • Grey matter – cell bodies, dendrites, unmyelinated axons, neuroglia • White matter – Myelinated axons histology.leeds.ac.uk Reflex Arcs • Reflex – Rapid, autonomic motor responses to stimuli – Somatic or visceral • Monosynaptic – Direct connection between afferent and efferent neurons • Polysynaptic – One or more interneurons involved Spinal Reflexes Neuronal Circuits • Diverging circuits – Signal is passed to many pathways • Converging circuits – Various signals influence one neuron • Reverberating circuit – One neuron in a series sends feedback to a previous neuron in the circuit • Serial and Parallel processing Disorders of the Nervous System • Multiple Sclerosis – Autoimmune attack of myelin on CNS axons • Neuronal Regeneration – Possible to regenerate axons of PNS – Regeneration tubes
