Phys Ch 8

  1. Nervous system
    is a complex network of nurons that form the rapid contol system of the body and carry electrical signals
  2. CNS Central Nervous system
    composed of the brain and spinal cord
  3. PNS Peripheral nervous system
    • Has Afferent sensory(to the brain) neurons that
    • bring info to the CNS and efferent nurons (out of the brain) that carry information away from the CNS back to various parts of the body
  4. Efferent neurons
    Somatic motor Nuerons
    control skeletal muscles
  5. Efferent nerons
    Automatic neurons
    • control smooth cardiac muscles glands, and some adipose tissue.
    • They are divided into sympathetic and parasympathetic branches
  6. Neurons
    have a cell body and organelles with a nucleus
  7. Dentrites
    recevie incoming signals
  8. Axon
    Transmits electrical signals from the cell body to the axon terminal
  9. Axon terminal
    neurotransmitters are released
  10. Synapse
    The region where an axon terminal meets its target cell
  11. Postsynaptic cell
    the target cell (after the synapse)
  12. Presynaptice cell
    the nueron that releases the chemical signal (before the synapse)
  13. Synaptic cleft
    the region between the postsynaptic and the presynaptic cell
  14. Axnoal transport
    Material like proteins and oragnelles is transported between the cell body and axon terminal
  15. Glial cells
    provide phyiscal support and direct the gtowth of the neurons durring repir and development
  16. Schwann Cells
    in PNS form insulating myelin sheaths around neurons
  17. Microglia cells
    found in CNS, Are modified immue cells that act as scavengers
  18. Oligodendrocytes
    Found in CNS, insulates the myelin shealths
  19. Astrocytes
    Found in CNS, makes up the Blood Brain Barrier(BBB) with tight junctions
  20. Ependymal cells
    found in CNS, form of stem cells(new cells) and back up effectived damaged nerve cells
  21. Nodes of Ranvier
    Are sections of uninsulated membrane occuring at intervals along the lenths of an axon
  22. Graded potentials
    • Are depolarizations or hyperpolarization whos strength is directly proportional to the strenght of the triggering event
    • Lose strenght as they move through cell
  23. Depolarzation
    • Positive
    • makes a neuron more likely to fire an action potential
  24. Polarization
  25. HyperPolarization
    make neurons less likely to fire an action potentioan (exceding)
  26. Action Potential
    • Are rapid electrical signals that travel undiminished in amplitude from cell body the axon terminals (no fading)
    • All or none principle
  27. All or none Principal
    • All stimuli great enough to bring the membrane to
    • threshold will produce action potentials of identical magnitude
  28. Rising Phase
    Of action potential is an increase of Na+ in the cell
  29. Falling Phase
    Of action potential is due to K+ flow out of the cell (repolorzation)
  30. Overshoot
    Is when the cell has become more positive than the outside (action potential)
  31. Absolute refratory period
    a brief period of time where a second action potential cannot be triggered no matter how large the stimulus
  32. Relative refractory period
    Higher than normal graded potential is required to trigger an action potential
  33. Excitatory Postsynaptic Potential (EPSP)
    occurs when sodium channels are opened and depolorizes a neuron making it easier to fire.
  34. Inhibitory Postsynaptic Potential (IPSP)
    results in local hyperpolarizations (Slow down)
  35. conduction
    Movement of an action petential through the axon at high speed
  36. Saltatorry conduction
    Jumping of action potentials from node to node
  37. Hyperkalemia
    Too much potassium in the blood
  38. Electrical synapses
    electrical signal passes directly from cytoplasm of one cell to another through gap junctions
  39. Chemical synapese
    Use neurotransmitters to carry info from one cell to the next diffusing across synaptic cleft.
  40. Cholinegeric neurons
    Secrete acetycholine
  41. Adernergic neurons
    secreate Norepinephrine, Glutamate GABA serotonin adenosine and nitric oxide
  42. Divergence
    when a presynaptic neuron synapses on a larger number of postsynaptic neurons
  43. Convergence
    When Several neurons provide input to a smaller number of postsynaptic neurons
  44. Spatial Summation
    Summation of simultaneous graded potentials from different neuron
  45. Temporal summation
    repeated graded potentails reaching the trigger zone one after the other
Card Set
Phys Ch 8