Essentials of Human Anatomy & Physiology Chapter 7 PDF

Essentials of Human Anatomy & Physiology Elaine N. Marieb Chapter 7 Lecture Slides in PowerPoint by...

Essentials of Human Anatomy & Physiology Elaine N. Marieb Chapter 7 Lecture Slides in PowerPoint by Jerry L. Cook, edited by BJS BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 1  Objectives 1. List the general functions of the nervous system 2. Explain the structural & functional classification of the nervous system 3. Define the central and peripheral nervous system with their major parts 4. Describe the structure of neuron 5. Describe the functional and structural classification of neurons 6. Describe the composition of grey & white matters BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 2  Master & Fast Control & Communication System BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 3  FUNCTIONS of the Nervous System Sensory input Gathering information Integration Process, interpret sensory input & decide action Motor output The response … muscles or glands BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 4 FUNCTIONS of the Nervous System Sensory input – gathering information ∙ To monitor changes occurring inside and outside the body ∙ Changes = stimuli Integration ∙ To process and interpret sensory input and decide if action is needed Motor output ∙ A response to integrated stimuli ∙ The response activates muscles or glands BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 5  STRUCTURAL CLASSIFICATION of the Nervous System Central nervous system (CNS) ∙ Brain ∙ Spinal cord Peripheral nervous system (PNS) ∙ Nerves: ∙ Cranial nerves ∙ Spinal nerves BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 6  ORGANIZATION (Divisions) of the Nervous System BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 7 BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 8 ORGANIZATION of the Central Nervous System (Brain & Spinal cord) Nervous System Peripheral Nervous System (Cranial & Spinal Nerves) Sensory - Afferent Sense Organs Motor - Efferent Autonomic Somatic Involuntary Voluntary Sympa- Parasym- thetic pathetic Cardiac & smooth Skeletal muscles & glands Muscles BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 9 BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 10 NEURON ANATOMY Cell body neuron =nerve cell ∙ Cells specialized to transmit messages Cell body ∙ Nucleus ∙ Large nucleolus BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 11 NEURON ANATOMY Extensions outside the cell body = Dendrites ∙ Dendrites – conduct Axon impulses toward the cell body ∙ Axons – conduct impulses away from the cell body BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 12 NEURON ANATOMY Axon terminals Branching ends Terminals contain _________ that are filled with _________ ? T&L Axon terminals BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 13 Pre and post synaptic cells T&L BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 14 Axons and Nerve Impulses ∙ Axons end in axonal terminals ∙ Axonal terminals contain vesicles with neurotransmitters ∙ Axonal terminals are separated from the next neuron by a gap ∙ Synaptic cleft – gap between adjacent neurons ∙ Synapse – junction between nerves BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 15 Nerve Fiber Coverings – PNS ∙ Schwann cells (T&L) – produce myelin sheaths in jelly-roll like fashion ∙ Nodes of Ranvier – gaps in myelin sheath along the axon BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 16  Neuron Classification: Structural & functional classification Interneuron (or Association Motoror (efferent) Sensory (afferent) neurons neurons) ∙∙ Found in CNS, from Carry impulses awaythe from the CNS sensory receptors ∙∙ Connect To CNS musclessensory & motor neurons & glands PNS CNS Sensory neuron Interneuron Motor neuron BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 17 Neuron Classification T&L Where are the cell bodies of sensory neurons? What would a collection of sensory neuron cell bodies be called? Where are the cell bodies of motor & inter neurons? Sensory neuron Interneuron Motor neuron BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 18 BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 19 Neuron Cell Body & Fibers CNS v PNS CNS PNS Clusters of cell bodies Nuclei Ganglia Bundles of fibers Tracts Nerves BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 20 BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 21 BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 22 Structural Classification of Neurons ∙ Multipolar neurons – many extensions from the cell body Figure 7.8a BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 23 Structural Classification of Neurons ∙ Bipolar neurons – one axon and one dendrite Figure 7.8b BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 24 Structural Classification of Neurons ∙ Unipolar neurons – one axon from the cell body Figure 7.8b BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 25 BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 26  Gray matter & White matter ∙ inmatter Gray CNS= cell bodies and unmylenated fibers or axonsin the CNS ∙ White matter = myelinated fibers or axons in the CNS Spinal Cord Brain Section Section BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 27 Functional Properties of Neurons Irritability ∙ ability to respond to stimuli Conductivity ∙ ability to transmit an impulse The plasma membrane at rest is polarized ie has fewer positive ions are inside the cell than outside the cell T&L What is this state called? BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 28  Objectives 7. Describe the events that lead to the generation of nerve impulse and its conduction from one neuron to another neuron 8. Define the reflex arc & its elements with typical example BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 29  THE NERVOUS SYSTEM HOW? PHYSIOLOGY BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 30  NERVE IMPULSES PHYSIOLOGY BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 31 Starting a Nerve Impulse Fig 7.9 1. Resting membrane is polarized (no stimulus/no activity) Na+ out K+ in Polarization: slightly negative charge inside the nerve membrane & slightly positive charge outside BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 32 Starting a Nerve Impulse 2. Stimulus initiates local Depolarization – a stimulus depolarizes the neuron’s membrane(stimulus/activity) Na+ in K+ out Depolarization: loss of the negative charge inside the nerve membrane (sudden change in electrical potential from negative to slightly positive inside the nerve) BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 33 Starting a Nerve Impulse 3. Depolarization & generation of AP (impulse) ∙A depolarized membrane allows sodium (Na+) to flow more inside the membrane and completely ∙The exchange of ions initiates an action potential in the neuron BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 34 Nerve Impulse Propagation 4. Propagation of AP ∙The impulse continues to move (is propagated) along the fiber or axon as in 2. BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 35 Nerve Repolarization 5. Repolarization ∙Potassium ions rush out of the neuron after sodium ions rush in , which repolarizes the membrane ∙Negative ions restored inside ∙Positive charge restored outside BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 36  6. Initial ionic conditions restored (charge is maintained or back to normal status)= Repolarization continuation to resting status ∙The sodium-potassium pump restores the original configuration or status (requires ATP) BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 37  The sodium-potassium pump 3 Na+ ions pumped out for every 2 K+ ions pumped in to the resting status BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 38 Membrane Potentials Review BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 39 BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 40  The Reflex Arc Fig. Definition, Components, Examples, & Types Definitions: Reflex – responses to stimuli that is ∙ rapid, ∙ predictable, ∙ involuntary Reflex arc – direct route from a sensory neuron, to an interneuron, to an effector BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 41  The Reflex Arc: 5 1. Receptor Components eg skin 2. Sensory (afferent) neuron STIMULUS 3. Integration 5. Effector … Center – muscle or 4. Motor (efferent) association gland neuron neuron= interneuron BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 42 Examples: 1. Simple patellar & 2. Complex Reflex Arcs Simple: Two Complex: Three neuron reflex neuron reflex Eg. Knee jerk BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Eg. Flexor/ Slide 43  Types of Reflexes & Regulation Autonomic reflexes (involuntary) ∙Smooth muscle regulation ∙Heart and blood pressure regulation ∙Regulation of glands ∙Digestive system regulation Somatic reflexes (voluntary) ∙Activation of skeletal muscles BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 44  Homeostasis & Negative Feedback (p.10) 4. Output 3. Input Control information sent information Center along efferent sent along pathway to afferent activate … pathway to … Receptor Effector 2. Change detected by receptor 5. Response of effector feeds back to influence the stimulus & 1. Stimulus produces return variable to change in variable homeostasis BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 45  Homeostasis & Negative Feedback (p.10) 4. Output 3. Input Control information sent information Center to sweat glands sent along and blood afferent vessels in skin pathway to hypothal-amus Receptor Effector 2. Change detected by thermo 5. Response ie receptors sweat & flushing, looses body heat by 1. Exercise or hot day evaporation & to  temp radiation … temp  BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 46  Go to Interactive CD...... BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 47 Continuation of the Nerve Impulse between Neurons ∙ Impulses are able to cross the synapse to another nerve ∙ Neurotransmitter is released from a nerve’s axon terminal ∙ The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter ∙ An action potential is started in the dendrite BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 48 Synapses For an electrical signal to pass from one excitable cell to another it must cross a synapse (synapsis = point of contact). Chemical Synapses Junction between 2 neurons is a chemical synapse … stimulation of the second (or postsynaptic) neuron is caused by a chemical released by the first (or presynaptc) neuron. Think & Link … what happens at a neuromuscular junction? BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 49  THE SYNAPSE Structures Synaptic End Bulb Synaptic cleft Post synaptic membrane BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 50 Summary of events at the Synapse 1. An electrical nerve impulse arrives at the axon terminal BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 51 Summary of events at the Synapse 2. A chemical neuro-transmitter in vesicles in the synaptic knob (terminal end) of the axon is released into the synapse 3. The neurotransmitter diffuses across the synapse and combines with receptor sites on the cell membrane of the next neuron BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 52 Summary of events at the Synapse 4. Neurotransmittor binds to receptor proteins on the post synaptic membrane BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 53 Summary of events at the Synapse 5. Ion chanels open and this causes polarzation or depolarzation (inflow of Na+) generating an electrical impulse which in turn is carried by this neuron's axon to the next synapse BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 54 Summary of events at the Synapse 6. A chemical inactivator within the cell body or dendrite of the receiving neuron quickly inactivates the neurotransmitter. BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 55 Summary of events at the Synapse ONE WAY TRANSMISSION Synapses ensure one‑way transmission of impulses in a living person. A nerve impulse cannot go backward across a synapse because there is no neurotransmitter released by the dendrites or cell body. Neurotransmitters can only be released by axons BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 56 Coming up … CENTRAL NERVOUS SYSTEM BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 57 SYNAPSE - Structures Synaptic end bulb... an enlarged knob or swelling contains membrane-enclosed bubbles (synaptic vesicles) containing neurotransmitter Synaptic cleft narrow gap between the axon terminal of the presynaptic neuron and the cell body or dendrite of the postsynaptic neuron is filled with extracellular fluid CB p.148 BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 58 SYNAPSE - Structures Postsynaptic membrane. membrane across the synaptic cleft (belonging to the dendrite or cell body of the postsynaptic neuron) has receptor proteins that combine with neurotransmitter molecules and trigger depolarization or hyperpolarization of the postsynaptic membrane. BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 59 SYNAPSE - Structures Synaptic End Bulb Synaptic cleft Post synaptic membrane BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 60  THINK SPOT Nice 2 Know T&L T&L BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 61 Nervous Tissue: CNS Neuroglia: (Support cells): ASTROCYTES ∙ Abundant, star-shaped cells ∙ Anchor neurons ∙ Form barrier between capillaries and neurons ∙ Control the chemical environment of the brain BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 62 Nervous Tissue: CNS Neuroglia: MICROGLIA ∙ Spider-like phagocytes ∙ Dispose of debris BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 63 Nervous Tissue: CNS Neuroglia: EPENDYMAL CELLS ∙ Line cavities of the brain and spinal cord ∙ Circulate cerebrospinal fluid BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 64 Nervous Tissue: CNS Neuroglia: OLIGOGENDRITES Produce myelin sheath around nerve fibers in the central nervous system BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 65 Nervous Tissue: PNS Supports: SATELLITE & SCHWANN CELLS Satellite cells ∙ Protect neuron cell bodies Schwann cells ∙ Form myelin sheath in the peripheral nervous system BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 66 Nerve Fiber Coverings – CNS ∙ Many fibres have myelin sheath– produced by.... (T&L) ∙ No neurilemma BJS edited from 2003 Pearson Education, Inc. publishing as Benjamin Cummings, Nov.2002 Slide 67