Nervous System; Fundamentals 3.21.16
Nervous System; Fundamentals 3.21.16 BSCI 201
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This 4 page Class Notes was uploaded by Brooke Sullivan on Sunday April 3, 2016. The Class Notes belongs to BSCI 201 at University of Maryland taught by Dr. Meredith Bohannon in Spring 2016. Since its upload, it has received 51 views. For similar materials see Human Anatomy and Physiology in Biological Sciences at University of Maryland.
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Date Created: 04/03/16
Nervous System: The Fundamentals 4/3/16 7:34 PM What does the nervous system do? • Sends information from stimulus to the brain by way of sensory, or afferent, nerves • Sends signals from the brain to motor nerves by way of motor, or efferent, nerves • Integrates information in the brain and spinal cord through interneurons • Pathway: Sensory Input – Integration – Motor Output Anatomy of the Nervous System • Brain • Spinal Cord • Integration Neurons • Cranial Nerves • Spinal Nerves • Ganglia Cells of the Nervous System • Neurons • Neuroglia • CNS: astrocytes, microglial cells, ependymal cells, oligodendrites • PNS: satellite cells, schwann cells • The Neuron • Composed of the soma, dendrites, and axon The Cell Body of the Neuron • Control center of the cell, as usual • Rough ER, Golgi Apparatus, and Nissl bodies are well developed within neurons • Dendrites • Inouts are received as action potentials (which are graded potential) • High surface areas • Axons • Send action potentials • One axon per neuron • Branchings from the axon are called axon collaterals • The very end of the axon is made up of terminal branches • Organization of Neurons in CNS and PNS • Groups of cell bodies in the CNS are called nuclei • Groups of cell bodies in the PNS are called ganglia • Axons in the CNS are called tracts • Axons in the PNS are called nerve fibers, or nerves (bundle of nerve fibers) • Astrocytes • Star shaped with many processes • Connect neurons to capillaries, help direct forming neurons, and clean up the space surrounding neurons • Microglial Cells • Immune response of CNS • When they are resting, they have many processes. When they become activates, it turns into amoeboid form, ten eventually takes the form and function of macrophages • Ependymal Cells • Line spinal cord cavities • Filter and circulate cerebrospinal fluid • Oligodenrites • Responsible for the myelin sheath on CNS neural axons • Neuroglia In The PNS • Satellite Cells: line cell bodies of neurons and are thought to function in similar ways as astrocytes • Schwann Cells: provide myelin sheath on PNS neurons • Functional Aspects of Neurons • Action potential; down the axon; arrives at terminal; neurotransmitters are released; another cell responds • Axonal transport • Not an action potential, but substances that need to move from one end of the cell to the other • Anterograde: cell body to terminal; kinesin • Retrograde: terminal to cell body; dynein • Myelin Sheath • Fatty substance covering the axons of long neurons • Acts as insulation • Its segmented nature speed up action potentials by 30x • Classifications of Neurons • Structural: multipolar, bipolar, unipolar • Functional • Sensory: unipolar; signal form receptors to brain • Motor: multipolar; signal from CNS to effector organ or skeletal muscle • Interneuron: multipolar; signal from sensory to motor neuron 4/3/16 7:34 PM 4/3/16 7:34 PM