Chapter 44 The Nervous System 2011 new(2)

Chapter 44 The Nervous System 2011 new(2) - Chapter 44- The...

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Unformatted text preview: Chapter 44- The Nervous System Learning Objectives 1. The organization of the Nervous System 2. The structure of Neurons 3. Mechanisms of Nerve Impulse Transmission 4. Synaptic Transmission 5. The Central Nervous System: Brain and Spinal Cord 6. The Central Nervous System: The Peripheral Nervous System A. Somatic Nervous System B. Autonomic Nervous System The Nervous System 1. Communication within animals is vitally important in integrating the various processes and structures. 2. Communication within animals occurs with the aid of 2 systems: The Nervous System and the Endocrine System 3. The nervous system is composed of specialized cells called neurons that make up the 2 majors components of the system: A. Central Nervous System (CNS)- brain and spinal cord B. Peripheral Nervous System (PNS)- neurons peripheral to the CNS- autonomic nervous system (involuntary motor neurons), somatic nervous system (voluntary motor neurons), sensory information (sensory neurons). tructure of Neurons: 1. They are small, specialized cells composed of three parts: A. Dendrites- numerous short processes which collect electrical signals and pass them on the cell body. B. Cell Body- integrates incoming signals, generates outgoing signal to axon. C. Axons- Pass electrical signals to dendrites or another effector cell (ie muscle cell), typically 1 axon per neuron but may be branched at the end of the process 2. Electrical signals move in a unidirectional way. Dendrites cell body - axons Important Point: Information or nervous impulses (technically called action potentials) flow one way from dendrites to cell body to axons. There can be integration of the nerve impulse at the level of the cell body. embrane Potentials 1. Ions are electrically charged + or -, eg Na + , Cl- , or K + ,proteins- . 2. Cells are full of ions as are the extracellular fluids surrounding the cells. Cells, therefore, possess an electrical charge. A difference in charge between the inside and outside of the cell creates a difference in electrical potential or voltage . This charge difference is also called a membrane potential . 3. Membrane potentials are measured in millivolts (mV). 1 mV = 1/1000 of a volt. 4. Membrane potentials are a form of potential energy. A flow of charge (ions) is called an electric current . 5. Remember, that ions move across membranes in response to 1) concentration gradients and 2) electrical gradients. So, when we have both types of gradients across a membrane we call it an electrochemical gradient . lectrochemical Gradients Across the Membrane of a euron at Rest (= Resting Potential) Sodium-Potassium pump (not shown) 1. The resting potential of a neuron is 65 mV....
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This note was uploaded on 02/12/2012 for the course BIOL 104 taught by Professor Dr.nevinaspinwall during the Fall '11 term at MO St. Louis.

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Chapter 44 The Nervous System 2011 new(2) - Chapter 44- The...

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