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Bellwork

Bellwork. List three things you know about the nervous system. Nervous System. Objectives. List functions of nervous system Explain structural and functional classifications Define CNS and PNS and list major parts. Master controlling and communicating system

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Bellwork

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  1. Bellwork • List three things you know about the nervous system.

  2. Nervous System

  3. Objectives • List functions of nervous system • Explain structural and functional classifications • Define CNS and PNS and list major parts

  4. Master controlling and communicating system • Works w/ Endocrine System to maintain homeostasis • Signals are electrical impulses • rapid, specific and cause almost immediate response

  5. Three overlapping functions of Nervous System • Sensory receptors to monitor changes • changes are stimuli • gathered info is sensory input • Processes/interprets sensory input and makes decisions (integration) • Effects a response by activating muscles or glands (motor output)

  6. Guided Practice • Work with your desk partner to research the structural classification of the nervous system. • Use the textbooks that are located on your desk (chapter 7).

  7. Structural Classification • Two subdivisions – • central nervous systems (CNS) • peripheral nervous systems (PNS) • CNS – brain and spinal cord in dorsal body cavity • integrating and command centers • Interpret incoming sensory information • Issues instructions • based on past experience and current conditions.

  8. CNS

  9. Structural Classification • PNS – • outside the CNS • Nerves serve as communication lines • Nerves extend from brain and spinal cord • Spinal nerves carry impulses to and from the spinal cord. • Cranial nerves carry impulses to and from the brain

  10. PNS

  11. Guided Practice • Read and take notes: • Create a flow chart to explain the functional classifications of the nervous system • Describe the 2 principal subdivisions • Describe the 2 subdivisions of the motor division • Describe 2 subdivision of the autonomic nervous system

  12. Functional classification • Only associated with PNS • Two principle divisions – • sensory (afferent) division • motor (efferent) divisions

  13. Functional classification • Sensory (afferent) division • Keeps CNS constantly informed • Nerve fibers convey impulses to the CNS • Somatic sensory – delivers impulses from the skin, skeletal muscles, and joints. • Visceral sensory – transmits impulses from visceral organs.

  14. Functional classification • Motor (efferent) division • Carries impulses from the CNS to effector organs, muscles, and glands. • Impulses activate muscles/glands • Has two subdivisions • Somatic nervous system – voluntarily control (ex. skeletal muscles) • Autonomic nervous system – regulates involuntary events (ex. smooth/cardiac muscles, glands) • two systems • sympathetic • parasympathetic

  15. Independent Practice • Draw picture in your notebook to represent the components of both the CNS and PNS. • Nervous System Vocabulary (listed on worksheet). Define in your own words in your notebook. Include an image for each definition. • Example

  16. Exit Slip • Create a flow chart using these terms: • Central Nervous System • Peripheral Nervous System • Motor division • Sensory division • Brain • Spinal Cord • Somatic Nervous System • Autonomic Nervous System • Parasympathetic Division • Sympathetic Division

  17. Bellwork • Create a flow chart using these terms: • Central Nervous System • Peripheral Nervous System • Motor division • Sensory division • Brain • Spinal Cord • Somatic Nervous System • Autonomic Nervous System • Parasympathetic Division • Sympathetic Division • How does the nervous system help the body maintain homeostasis? Explain your answer. • Once you have answered the BW questions, please continue working on any work not completed in class yesterday. (flow chart or doodle definitions

  18. Objectives • Compare/contrast structure/function of the nervous system tissue (supporting cells) • Describe the structure of a neuron and its important anatomical regions

  19. Nervous Tissue • Two principle types of cells • Supporting cells • Neurons • Supporting Cells • Collectively called neuroglia • Provides support, insulation, and protection • Not able to transmit nerve impulses • Never lose their ability to divide

  20. Guided Practice • Using your text book, preview, close read, and take notes to do the following: • List and describe supporting cells of the CNS. • List and describe supporting cells of the PNS. ***Leave room to expand your notes. ***

  21. Types of supporting cells (CNS) • Astrocytes • Star-shaped • Abundant • Cling to neurons • Make up nearly ½ the neural tissue • Braces/anchors neurons to nutrient supply lines (blood capillaries) • Forms a living barrier between capillaries and neurons • Protect neurons from harmful substances • Help control the chemical environment in brain

  22. Types of supporting cells (CNS) • Microglia • Spiderlike • Phagocytic (dispose of debris) • Ependymal cells • Line cavities of brain and spinal cord • Beating cilia helps to circulate the cerebrospinal fluid

  23. Types of supporting cells (CNS) • Oligodendrocytes • Wrap tightly around nerve fibers • Produces fatty insulating coverings (myelin sheaths)

  24. Types of supporting cells (PNS) • Two major varieties • Schwann cells form myelin sheaths around nerve fibers that extend from the CNS • Satellite cells act as protective/ cushioning cells

  25. Independent Practice-Doodle Definitions • Draw a picture for each of the members of the neuroglia family: • Astrocyte • Ependymal • Microglia • Oligodendrocyte • Schwann cell • Satellite cell • The picture should be anything that can help you remember what each thing does or looks like. For example microglia could be a spider.

  26. Guided Practice • Card game to review Nervous Tissue • Teacher will give a clue and you will hold up the card that coordinates with the description.

  27. Anatomy of Neurons • AKA Nerve Cells • Highly specialized to transmit messages (nerve impulses) from one part of the body to another. • Common Features • Neurons NEVER touch other neurons • Cell body contains nucleus and is metabolic center of the cell. ( if it is damaged the cell dies and is not replaced) • 1+ slender processes (fibers) extending from cell body

  28. Anatomy of Neurons • Dendrites-Processes that conduct electrical currents toward the cell body • Axons-Processes that generate nerve impulses and conduct them away from the cell body

  29. Anatomy of neurons • Axonal Terminal-Location where tiny vesicles store neurotransmitters • Synaptic Cleft-location where axonal terminal is separated from the next neuron by a tiny gap

  30. Anatomy of Neurons • Myelin sheath- • Myelin-whitish, fatty material covering nerve fibers • Protects and insulates the fibers • Increases the transmission rate of nerve impulses • Formed by many individual cells (oligodendrocytes or Schwann) • Gaps or indentations at regular intervals (nodes of Ranvier)

  31. Independent Practice • Draw, label and describe the parts of a neuron • Explain how a neuron interacts with other cells

  32. Exit Slip • __________________ consists of the nerves extending from the brain and spinal cord. • _________________ includes cells that support, insulate, and protect neurons and is also known as glia. • _________________ is the tiny gap that separates each axonal terminal from the next neuron. • ________________ is the membrane that encloses the axon. • ________________ are the membrane that cover the brain and spinal cord.

  33. Bellwork • Compare and contrast the cells of the nervous system (ex. Description and Function)

  34. Objectives • Classify neurons based on structure and function • Describe functional anatomy of brain and spinal cord

  35. Independent Practice • Create a chart to compare • 1: motor, interneurons, and sensory • 2: uni, bi and multipolar neurons

  36. Functional classification of neurons • Neurons grouped based on nerve impulse direction • Motor (efferent) neurons • Carry impulses from the CNS to the viscera and/or muscles and glands • Interneurons (association neurons) • Connect motor and sensory neurons in neural pathways. • Sensory (afferent) neurons • to go toward • Carry impulses from sensory receptors (internal organs or the skin) to the CNS area

  37. Functional classification of neurons • Sensory neurons continued • Dendrite endings associated with specialized receptors are activated by specific changes • Skin (cutaneous sense organs) • Pain receptors • Most numerous • Muscles/tendons (proprioceptors “one’s own”) • Detect stretch/tension in skeletal muscles • Info. sent to brain for adjustments to balance and posture.

  38. Structural classification of neurons • Based on number of processes extending from the cell body. • Multipolar Neuron • Several processes • Most common structural type • Bipolar Neuron • Two processes (axon and a dendrite) • Rare in adults • only in the eye and ear

  39. Structural classification of neurons • Unipolar Neurons • Single process emerging from cell body • Very short • divides almost immediately into proximal (central) and distal (peripheral) fibers • small branches at the end function as dendrites • Remainder of peripheral processes and the central process function as axons. (in this case, the axon conducts impulses both toward and away from the cell body)

  40. Functional Anatomy of the Spinal Cord • Cylindrical • 17 inches long • Continuation of brain stem • Two-way conduction pathway to and from the brain. • Major reflex center • Cushioned and protected by meninges • Meningal coverings extend well beyond the end of the spinal cord

  41. Functional Anatomy of the Brain • 4 major regions – • cerebral hemispheres • diencephalon • brain stem • cerebellum

  42. Cerebral Hemispheres • Most superior part of the brain • Obscure most of the brain stem • Elevated ridges of tissue called gyri seperated by shallow grooves called sulci • Deeper grooves called fissures which separate large regions • Other fissures divide each cerebral hemisphere into a number of lobes (named for cranial bones over them)

  43. Diencephalon • Interbrain • Sits anterior to the brain stem • Enclosed by the cerebral hemispheres • Major structures: • Thalamus • Relay station for sensory impulses • Hypothalamus • Plays a role in the regulation of body temperature, water balance, and metabolism. • Center for many drives and emotions (thirst, appetite, sex, pain, and pleasure centers) • Epithalamus • Forms cerebrospinal fluid

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