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The Nervous System

The Nervous System. Central Nervous System (CNS) Peripheral Nervous System (PNS). Do Now:. Get Your Clicker! Contract a K-W-L chart on loose-leaf List everything you already K now about the Nervous System in the K-column List everything you Want to know in W -column. Functions.

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The Nervous System

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  1. The Nervous System Central Nervous System (CNS) Peripheral Nervous System (PNS)

  2. Do Now: • Get Your Clicker! • Contract a K-W-L chart on loose-leaf • List everything you already Know about the Nervous System in the K-column • List everything you Want to know in W-column

  3. Functions • Monitors internal and external environments • Integrates sensory information • Coordinates voluntary and involuntary responses of other organ systems • 2 subdivisions: • CNS – brain and spinal cord • Intelligence, memory, emotion • PNS – all other neural tissue • sensory, motor

  4. Receptors and Effectors • Receptors – receive sensory info • Afferent division – carries info from sensory receptors to the CNS • Efferent division – carries info from CNS to PNS effectors (muscles, glands, adipose) • Somatic Nervous System (SNS) • Controls skeletal muscles (voluntary) • Autonomic Nervous System (ANS) • Controls involuntary actions • Sympathetic Division (increase heart rate) • Parasympathetic Division (decreases heart rate)

  5. Classwork: • Construct a flow chart detailing the direction in which information flows in the nervous system

  6. The sensory part of the PNS is... • Somatic division • Sympathetic division • Parasympathetic • Afferent division • Efferent division • Control center

  7. The fight or flight response is the... • Somatic division • Sympathetic division • Parasympathetic division • Afferent division • Efferent division • Control Center

  8. A change in ambient temperature would be detected by • Somatic division • Sympathetic division • Afferent division • Efferent division • Control Center

  9. Label Neuron • Read the functions to determine the structure of a typical neuron

  10. Neurons • Communicate w/other neurons • Soma-Cell body • Dendrites - receive info • Axon- sends signal to synaptic terminals (terminal buds) • Synapse – site of neural communication (gap) • Myelin – fatty insulation • Node of Ranvier – exposed axon between myelin • 3 structural types: • Multipolar – multiple dendrites & single axon (motor neurons) • Unipolar – continues dendrites & axon, cell body lies to side (sensory neurons) • Bipolar – one dendrite and one axon w/cell body between them (special senses)

  11. Types of Neurons • 3 functional types • Sensory – afferent division • info about surrounding environment • position/movement skeletal muscles • digestive, resp, cardiovasc, urinary, reprod, taste, and pain • Motor – efferent division (response) • skeletal muscles • cardiac and smooth muscle, glands, adipose tissue • Interneurons • Brain and spinal cord - memory, planning, and learning

  12. Neuroglia • Regulate environment around neurons; can be phagocytes; actively divide • Functions in CNS: • maintains the blood-brain barrier • create myelin (lipid) to coat axon • Nodes – gaps between myelinated sections • Internodes – areas covered in myelin • Phagocytic cells • Secrete cerebrospinal fluid (CSF)

  13. The most common type of neuron is • multipolar • bipolar • unipolar

  14. The part of the neuron that has receptor proteins on its surface is • Dendrites • soma • axon • Myelin sheath

  15. The part of the neuron that increases the speed of transmission is the • Dendrites • soma • axon • Myelin sheath

  16. Complete Action Potential POGIL • Remember: • Discuss each question and answer with your group • Use the information from the models to support your responses • You may use any resources to assist you

  17. Membrane Potential • Cells are polarized (measured in volts) • Resting potential of neuron -70mV • Remains stable due to Na+/K+ Pumps Leak channels – always open (K+ diffuses out) K+ Proteins- Net - charge Na+ Cl- Gated channels – open/closed under specific circumstance

  18. Changes in Membrane Potential • Depolarization • Stimulus opens Na+ gated channels • increase +charge of cell towards 0mV • Action Potentials • Affects entire surface of cell membrane • (+) feedback as nerve impulse continues • Hyperpolarization • Stimulus opens K+ gated channels • Increases –charge (from -70mV to -80mV) • Restores resting potential

  19. Action Potential: All or Nothing Principal • Only skeletal muscle fibers and neuron axons have excitable membranes • Graded potential increases pressure until sufficient enough to reach action potential • Resting potential (-70mV) • Reaches Threshold (-60mV) • Refractory Period – cell cannot respond to stimulation • Depolarization • Repolarization • Continuous Propagation • chain rxn until reaches cell memb • Unmyleinated – 1m/s (2mph) • Salatory Propagation • Myelinated (blocks flow of ions except at nodes) • Action potential jumps from node to node • 18-40m/s (30-300mph)

  20. Neural Communication • Nerve impulse – info moving in the form of action potentials along axons • At end of axon the action potential transfers to another neuron or effector cell by release of neurotransmitters from synaptic terminal (only occur in 1 direction) • Activity of neuron depends on balance between: • Excitatory neurotransmitters - depolorization • ACh & Norepinephrine • Inhibitory neurotransmitters -hyperpolarization • Dopamine, Seratonin, GABA

  21. An excitatory neurotransmitter • Increases electrical impulse • Causes the release of more neurotransmitters • Is released in a synaptic cleft • All of the above

  22. The resting membrane potential inside a neuron is • 0mV • 30mV • -60mV • -70mV

  23. After stimulus, the rush of sodium ions into the cell is called • depolarization • repolarization • hyperpolarization

  24. The action potential is propagated by • More Na+ rushing into the cell • K+ leaving the cell • Neurotransmitters binding to dendrite • Vesicles release neurotransmitters

  25. The cell’s charge at the peak depolarization is • 0mV • 30mV • -60mV • -70mV

  26. During repolarization • The resting potential is restored • K+ diffuse out of cell • The cell membrane becomes negatively charged again • All of the above

  27. Once the action potential reaches the axon terminal, the signal will be carried to the next neuron by • Na+ ions • Neurotransmitters • K+ ions • All of the above

  28. If an excitatory neurotransmitter binds to neuron number one, how will that affect the number of neurotransmitter released? • more • less • No effect at all

  29. 0 of 30 If previous neuron releases GABA, an inhibitory neurotransmitter, how will that affect neuron #2 • Increase electrical stimulus • Decrease electrical stimulus • Increase neurotransmitters released • decreased neurotransmitters released • 1&3 • 2&4

  30. Reflexes • Reflex – involuntary response to stimulus w/o requiring the brain • Reflex arc- sensory neuron Interneuron motor neuron (opposes initial stimulus) • Ex. Knee jerk reflex • Babinski reflex (infants only) • Stroke sole of foot  toes fan out • Plantar reflex (adults only) • Stroke sole of foot toes curl • Signals sent to brain by interneurons allow for control • Ex. Toilet training, gag, blink

  31. Testing reflexes activity

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