Surveyofanatomyandphysiologychap9parttwo 131021171528-phpapp01
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The document discusses the nervous system and specialized cells called neuroglia or glial cells. There are four main types of glial cells in the central nervous system that perform specialized functions like metabolic and structural support, attacking microbes and removing debris, covering and lining cavities, and making myelin insulation. There are also two main types of glial cells in the peripheral nervous system that make myelin and support cells. Neurons are the basic functional units of the nervous system and have specific parts including the cell body, dendrites, and axon that each perform distinct functions. Neurons communicate via electrical or chemical synapses to transmit signals.
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- 1. The Nervous System: The Body's Control Center 9
- 3. Specialized cells in Central Nervous SystemCentral Nervous System called neuroglia, or glial cells, perform specialized functions. Four types: Neuroglia-Glial CellsNeuroglia-Glial Cells
- 4. Specialized cells in nervous system called neuroglia, or glial cells, perform specialized functions Nerve Tissue-Nerve Tissue- Glial CellsGlial Cells Metabolic andMetabolic and structural supportstructural support
- 5. Specialized cells in nervous system called neuroglia, or glial cells, perform specialized functions Nerve Tissue-Nerve Tissue- Glial CellsGlial Cells Attack MicrobesAttack Microbes and removeand remove debrisdebris
- 6. Specialized cells in nervous system called neuroglia, or glial cells, perform specialized functions Nerve Tissue-Nerve Tissue- Glial CellsGlial Cells Cover and lineCover and line cavities ofcavities of nervous systemnervous system
- 7. Specialized cells in nervous system called neuroglia, or glial cells, perform specialized functions Nerve Tissue-Nerve Tissue- Glial CellsGlial Cells Makes lipidMakes lipid insulation calledinsulation called myelinmyelin
- 8. Specialized cells in Peripheral Nervous SystemPeripheral Nervous System called neuroglia, or glial cells, perform specialized functions. Two types: Neuroglia-Glial CellsNeuroglia-Glial Cells
- 9. Specialized cells in nervous system called neuroglia, or glial cells, perform specialized functions Nerve Tissue-Nerve Tissue- Glial CellsGlial Cells Makes myelinMakes myelin for PNSfor PNS
- 10. Specialized cells in nervous system called neuroglia, or glial cells, perform specialized functions Nerve Tissue-Nerve Tissue- Glial CellsGlial Cells SupportSupport cellscells
- 11. Figure 9-2 Glial cells and their functions.
- 12. Each part of neuron has specific function Body/SomaBody/Soma: cell metabolism DendritesDendrites: receive information from the environment AxonAxon: generates and sends signals to other cells Nerve Tissue-TheNerve Tissue-The NeuronNeuron
- 13. Figure 9-3 A neuron connecting to a skeletal muscle. Each part of neuron has specific function: Axon terminalAxon terminal: where signal leaves cell SynapseSynapse: where axon terminal and receiving cell combine
- 14. Neurons Neurons are classified by how they look (structure) or what they do (function) Neurons are classified by how they look (structure) or what they do (function)
- 15. Neurons can use their ability to generategenerate electricityelectricity to send, receive, and interpret signals How Neurons WorkHow Neurons Work
- 16. Neurons are called excitableexcitable cells; this simply means that if cell is stimulated it can carry small electrical chargesmall electrical charge. Each time charged particles flow across a cell membrane, there is tiny charge generatedtiny charge generated How Neurons WorkHow Neurons Work
- 17. All three muscleAll three muscle types are excitable cells, as are many gland cells Cells are like miniatureminiature batteriesbatteries, able to generate tiny currents simply by changing permeability of their membranes How Neurons WorkHow Neurons Work
- 18. Series of permeabilitypermeability changeschanges within the cell and the resultant changes in the charge across the cell membrane The Action PotentialThe Action Potential
- 19. The Action PotentialThe Action Potential • Polarized • Depolarized • Repolarization • Hyperpolarization • Refractory Changes in the Cell
- 20. A cell that is notnot stimulatedstimulated or excited is called a resting cellresting cell; it is said to be polarizedpolarized It has a difference in charge across its membrane, being moremore negative insidenegative inside than on the outside cell Resting Cell-PolarizedResting Cell-Polarized
- 21. When cell is stimulated, sodiumsodium gatesgates in the cell membrane spring openopen, allowing sodium to travel across membrane Sodium bits are positively chargedpositively charged, so cell becomes more positive as they enter Stimulated Cell-Stimulated Cell- DepolarizedDepolarized
- 22. Sodium gates close after a few minutes and potassium gates openpotassium gates open; potassium leaves cell, taking its positive charge with it RepolarizationRepolarization
- 23. If cell becomes more negative than resting it is called hyperpolarizedhyperpolarized Action potential (AP) is cell moving through depolarization,depolarization, repolarizationrepolarization, and hyperpolarizationhyperpolarization HyperpolarizationHyperpolarization
- 24. Cell cannot accept another stimulus until it returns to its resting state, and this time period when it cannot accept another stimuluscannot accept another stimulus is called refractoryrefractory period Refractory PeriodRefractory Period
- 25. Figure 9-4 The action potential- page 209.
- 26. Speed of impulse conduction is determined by amount ofamount of myelinmyelin and diameter ofdiameter of axonaxon Myelin IncreasesMyelin Increases ConductionConduction
- 27. Myelin is lipidlipid insulationinsulation or sheath formed by oligodendrocytesoligodendrocytes in CNS and… Schwann celSchwann cells in PNS Myelin IncreasesMyelin Increases ConductionConduction
- 28. Myelinated axon vs.Myelinated axon vs. UnmyelinatedUnmyelinated Myelin is essential for speedy flow of Action potential down the axon Un-myelinated axon has to depolarize each and everyeach and every millimetermillimeter of axon .5 meters/second.5 meters/second 100 meters/second100 meters/second
- 29. Figure 9-5 Wider axons conduct faster Diameter of axonDiameter of axon also affectsalso affects speed of action potential flow; wider the diameter of axon, faster the flow of ions
- 30. Figure 9-5 Impulse conduction via myelinated axon. Nerve impulseNerve impulse jumpsjumps from the bare areas between myelin sheath called the Nodes of RanvierNodes of Ranvier which is FASTER
- 31. Watch Video “How Synapses Work” https://www.youtube.com/wa How Synapses WorkHow Synapses Work
- 32. When AP* arrives at axon terminal, terminalterminal depolarizes and calciumdepolarizes and calcium gates open;gates open; calcium ions flows into cell; when calcium flows in, it triggers change in terminal How Synapses WorkHow Synapses Work *Action potential
- 33. There are tiny sacs in terminal called vesiclesvesicles that release their contents from cell when calcium flows in How Synapses WorkHow Synapses Work VesiclesVesicles
- 34. Vesicles are filled with molecules called neurotransmittersneurotransmitters that send signal from neuron across synapse to next cell in line How Synapses WorkHow Synapses Work
- 35. Once released the neurotransmitter binds to receptors on postsynaptic membrane. Each neurotransmitter has a specific receptor How Synapses WorkHow Synapses Work
- 36. The specific neurotransmitter determines whether the impulse continues which is called EXCITATION allowing Sodium (Na+) channels to open and membrane is depolarized and How Synapses WorkHow Synapses Work Sodium channels
- 37. The specific neurotransmitter determines whether the impulse is blocked which is called INHIBITION allowing Potassium (K+) channels to open and the impulse STOPS How Synapses WorkHow Synapses Work Potassium channels
- 38. The receptor then releases the neurotransmitter after which it is reabsorbed by the synaptic knobs and recycled or destroyed by enzymes. How Synapses WorkHow Synapses Work Enzymes
- 39. Use of neurotransmitters is called chemicalchemical synapsesynapse because chemicals carry informationchemicals carry information from one cell to another Chemical SynapseChemical Synapse
- 40. Figure 9-6 . Step 1: The impulse travels down the axon. Step 2: Vesicles are stimulated to release neurotransmitter (exocytosis). Step 3: The neurotransmitter travels across the synapse and binds with the receptor site of post synaptic cell. Step 4: The impulse continues down the dendrite. Chemical SynapseChemical Synapse
- 41. NeurotransmittersNeurotransmitters Acetylcholine Generally excitatory, but sometimes excitatory Norepinephrine May be excitatory or inhibitory depending on receptor Epinephrine May be excitatory or inhibitory depending on receptors Serotonin Generally inhibitory Endorphins Generally inhibitory
- 42. Clean up at theClean up at the SynapseSynapse After neurotransmittersneurotransmitters create a nerve impulse at the synapse, enzymes “reuptake” orreuptake” or clean upclean up the chemicals and use them again
- 43. Selective serotonin reuptake inhibitors (SSRIs) are medications thatmedications that preventprevent cleanupcleanup of neurotransmitter serotonin from synapses, thus increasing effects of serotonin on receiving cell AntidepressantsAntidepressants
- 44. Electrical vs ChemicalElectrical vs Chemical SynapseSynapse • Cells do not need chemicals to transmit information from one cell to another • Can transfer info because of special connection called GAP JUNCTION • Cells do not need chemicals to transmit information from one cell to another • Can transfer info because of special connection called GAP JUNCTION Gap junction
- 45. Electrical SynapseElectrical Synapse Electrical synapses with gap junction are found in the intercalated discs of cardiac muscle cells Electrical synapses with gap junction are found in the intercalated discs of cardiac muscle cells
- 46. Electrical vs ChemicalElectrical vs Chemical SynapseSynapse
- 47. In ClassIn Class WORKSHEETWORKSHEET Complete the worksheet using ONLY YOUR NOTES-NO TEXTBOOK or LAP TOPS, TABLETS You will not need to complete the Chapter 9 worksheets for credit but use simply for STUDY GUIDE for your test
- 48. EXAM-Chapters 6 & 7EXAM-Chapters 6 & 7 Your exam is Tuesday Oct 29 at 9:30 a.m. It will have questions from: •Power Point Presentations on Chapter 6 & 7 •Essay on functions of skeletal system •Explain osteoporosis and cells of bone formation •Step by step of Muscle contraction •Diagram on specific joint •Extra credit: MUSCLE TONE page 149 in your textbook