Power Point Lecture Slides Prepared by Patty BostwickTaylor
Power. Point® Lecture Slides Prepared by Patty Bostwick-Taylor, Florence-Darlington Technical College CHAPTER 7 The Nervous System PPT-A © 2012 Pearson Education, Inc. This ppt: 7 slides Total = 34 slides for 2 hour
PPT-A OUTLINE I. Overall Functions II. NS Organization III. Nervous Tissue A. Sensory A. Structural A. Cells B. Integration B. Functional B. Terminology C. Motor C. Functional Classification IV. Physiology A. Electrical Properties B. Action Potentials PPT-B OUTLINE V. Central Nervous System A. Brain B. Spinal Cord © 2012 Pearson Education, Inc. VI Peripheral Nervous Sys A. Nerves B. Autonomic NS
I. Overall Functions of the Nervous System A. Sensory input = Information in from body using Sensory Neurons B. Integration = make sense of information & make decisions on what to do using Interneurons (Association Neurons) C. Motor output = instructions out from Brain to body (mostly muscles) using Motor Neurons © 2012 Pearson Education, Inc.
II. Organization of the Nervous System A. Structural Classification 1. *Central nervous system (CNS) = Brain and Spinal Cord • *Function Integration = making sense of what is happening 2. *Peripheral nervous system (PNS) = Nerves • *Functions: Sensory information in to CNS AND Motor instructions out to organs © 2012 Pearson Education, Inc.
III. Nervous Tissue Structure & Function: A. Nervous Tissue Cells 1. *Neuroglia (glial): Support Functions Support & help provide nutrients Electrical Insulate Protect from microbes 2. Neurons a. Functional Characteristics i) Irritability: Can be Stimulated ii) Conductivity: Can send electrical messages b. Parts– i) *Cell body ii) *Dendrites: Describe and give function © 2012 Pearson Education, Inc.
b. Parts– … iii) *Axons: Synapse • Axon Terminals with Vesicles containing Neurotransmitters c. Synaptic cleft = Synapse—gap between adjacent neurons or neuron and an organ d. Myelin sheath = cell membrane made of lipids wraps multiple time around axon • Function: electrical insulation © 2012 Pearson Education, Inc.
Mitochondrion Dendrite Cell body Nissl substance Axon hillock Axon Neurofibrils Nucleus Collateral branch One Schwann cell Axon terminal Node of Ranvier Schwann cells, forming the myelin sheath on axon (a) © 2012 Pearson Education, Inc. Figure 7. 4 a
Neuron cell body Dendrite (b) © 2012 Pearson Education, Inc. Figure 7. 4 b
B. Functional Classification of Neurons 1. *Sensory Neurons: • Receptors: modified cells that take in information and gives it to sensory neurons 2. *Interneurons (association neurons): • Make sense of sensory information and decide if action is needed • Connect sensory and motor neurons 3. *Motor Neurons send instructions to organs, including muscles What are the 3 functional types of neurons? Explain the function of these neuron types. What are Receptors and give 3 examples? © 2012 Pearson Education, Inc. Spinal Cord and Nerve: Show the interactions between sensory neurons, interneurons, and motor neurons
Central process (axon) Cell body Sensory neuron Spinal cord (central nervous system) Ganglion Dendrites Peripheral process (axon) Afferent transmission Interneuron (association neuron) Peripheral nervous system Receptors Efferent transmission Motor neuron To effectors (muscles and glands) © 2012 Pearson Education, Inc. SPINAL CORD & NERVE Figure 7. 6
IV PHYSIOLOGY: Communication Between Neurons and between Neurons and other Cells 2 STEPS • Action Potential • Transmission of Message across Synaptic Cleft + Na+ _ Na+ K+ K+ K+ Na+ Na+ K+ K+ Na+ Piece of an AXON A. The Action Potential 1. The Resting Neuron– Not sending Action Potential a. Inside Neuron next to membrane: • More K+ (less K+ outside) a. Outside cell membrane: i) More Na+ (less Na+ inside) © 2012 Pearson Education, Inc. Na+
Action Potential … 2. Stimulus: maybe sensory or neurotransmitter from an adjacent neuron 3. Depolarization = Sodium moves from its high concentration outside the neuron to its low concentration t inside neuron STIMULUS _ © 2012 Pearson Education, Inc. Na+ + Na+ K+ K+ Na+ Na+ K+ K+ K+ Na+
Action Potential … 4. Repolarization • Potassium diffuses from its High concentration inside the neuron to its Low concentration outside of the neuron + K+ _ Na+ K+Na+ K+ K+ Na+ Na+ OVERALL: In one part of the axon, Na moves in immediately followed by K moving out. Then the next part of the axon does the same … all the way to the axon end © 2012 Pearson Education, Inc.
ACTION POTENTIAL IS LIKE THE “WAVE” AT A SPORTS STADIUM • People at one end of stadium raise their arms up and then down • Next group of people adjacent to the first then raise their arms up and then down • Next group of people …… Up and Down • … UP and Down • Finally the last group of people at the opposite end of the stadium raise there arms up and then down Stadium = Axon Arms Up = Na+ Diffuses into cell Arms Down = K+ Diffuses out of cell © 2012 Pearson Education, Inc.
Figure 11. 12 Propagation of an action potential (AP) showing change of charges across the axon membrane. 5. Redistribution of ions Initial ionic conditions, with potassium inside and sodium outside, are restored using the sodiumpotassium pump. PUMP Cell Outside Na+ K+ Cell Inside © 2012 Pearson Education, Inc. © 2013 Pearson Education, Inc.
C. Transmission of a Signal at Synapses: When action potential reaches the axon terminal, THEN must get the message across the synapse to the receiving neuron or cell Neuron #1 Axon terminal Ca+ Neuron #2 © 2012 Pearson Education, Inc. Dendrite Action Potential Arrives at Axon Terminal. Ca+
Transmission of a Signal at Synapses … (1) Vesicles move to membrane and do EXOCYTOSIS) Axon terminal Syna p Vesicles cleft tic 1 Ca+ Dendrite © 2012 Pearson Education, Inc. Ca+ Ca+ Figure 7. 10, step 1
2 Vesicle fuses with plasma membrane. Ca+ Synaptic cleft Axon terminal of Neuron #1 Ca+ Neurotransmitter molecules Dendrite or Neuron #2 © 2012 Pearson Education, Inc. Figure 7. 10, step 2
2 Vesicle EXOCYTOSIS Transmitting neuron fuses with plasma 3 Neurotransmembrane. mitter is Ca+ released into synaptic cleft. Synaptic cleft Neurotransmitter molecules Dendrite Receiving neuron © 2012 Pearson Education, Inc. Figure 7. 10, step 3
Transmission of a Signal at Synapses , , , (4) Neurotransmitters diffuse across to dendrite of neuron or to muscle cells Axon Terminal Dendrite © 2012 Pearson Education, Inc.
AXON TERMINAL 5 Ca+ Neurotransmitter binds to 2 nd Cell. Synaptic cleft Dendrite © 2012 Pearson Education, Inc. Figure 7. 10, step 4
Transmission of a Signal at Synapses … (6) The 2 nd neuron OR other cell (like muscle cell) has received the message and, then, if it is a neuron it may send its own Action potential © 2012 Pearson Education, Inc.
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