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  1. Sensory receptors
    detect stimulus
  2. motor receptors
    respond to stimulus
  3. Sensory neurons
    carry impulses from sensory receptors to the central nervous system
  4. motor neurons
    carry impulses from the CNS to effectors
  5. Interneurons
    help provide more complex reflexes and higher associative learning
  6. sensory and motor neurons constitute the ______
    Peripheral nervous system
  7. 2 divisions of autonomic nervous system
    • 1. sympathetic- fight or flight
    • 2. Parasympathetic-resting and relaxing
    • these two counter balance each other
  8. the ______consists of the brain and spinal cord
    central nervous system
  9. the ______ consists of sensory and motor neurons
    peripheral nervous system
  10. Somatic NS
    stimulates skeletal muscles
  11. Autonomic NS
    stimulates smooth and cardiac muscles, as well as glands.
  12. structure of a neuron
    • cell body- enlarged part containing nucleus
    • dendrites- short, cytoplasmic extensions that receive stimuli
    • axon- Single long extension that conducts impulses away from cell body
  13. Neurons are supported both structurally and functionally by cells called _________
  14. Schwann cells
    produce myelin sheaths in peripheral nervous system
  15. oligodendrocytes
    produce myelin sheaths in the central nervous system
  16. In the CNS, myelinated axons form ______ matter
  17. In the CNS, dendrites/ cell bodies form _____ matter
  18. the inside of the cell is more negative/ positive that the outside because of what 2 things
    • negative
    • 1. sodium-potassium pump= brings two K+ into cell for every 3 Na+ pumped out
    • 2. Ion channels= Allow more K+ to diffuse out than Na+ to diffuse inward.
  19. the cytoplasmic side of a cell is _______ with respect to the outside. so it is a _________ pole
  20. the extracellular fluid side of a cell is ________ with respect to the cytoplasm, so it is a ______ pole
  21. When a neuron is not being stimulated, it maintains a ______
    resting potential
  22. what is the normal range of resting potentials?
    • -40 to -90 millivolts
    • average about -70 mV
  23. balance between diffusional and electrical forces leads to the ___ _____
    equilibrium potential
  24. What are the two types of potentials?
    • graded potentials
    • action potentials
  25. Graded potentials
    small transient changes in membrane potential due to activation of gated ion channels
  26. chemically-gated or ligand-gated channels
    ligands are hormones or neurotransmitters that bind to receptors and cause channels to open, thus causing changes in cell membrane permeability
  27. Depolarization
    makes the membrane potential more positive
  28. hyperpolarization
    makes it more negative
  29. summation
    is the ability of graded potentials to combine
  30. Action potentials
    result when depolarization reaches the threshold potential
  31. the action potential is caused by ___-____ ___ ____
    voltage-gated ion channels
  32. two types of voltage gated channels
    • voltage gated Na+ channels- depolarization
    • voltage-gated K+ channels- hyperpolarization
  33. When the threshold voltage is reached, ___-___ ___ ____ open rapidly
    voltage-gated sodium channels
  34. When the threshold voltage is reached which type of channel opens slowly?
    voltage-gated potassium (K+) channel
  35. three phases of action potential
    • 1. rising
    • 2. falling
    • 3. undershoot
  36. ____ ____ are always separate, all-or-none events with the same amplitude
    action potentials
  37. the intensity of a stimulus is coded by the ________ of action potentials
  38. Each action potential, in its rising phase, reflects a reversal in membrane ______
  39. meanwhile, during the _______ phase, the previous region repolarizes back to the resting membrane potential.
  40. Two ways to increase velocity of conduction
    • 1. axon has a large diameter-less resistance to flow. found primarily in invertebrates
    • 2. axon is myelinated-action potential is only produces at the nodes of Ranvier. Impulse jumps from node to node- saltatory conduction.
  41. synapses
    intercellular junctions
  42. presynaptic cell
    transmits action potential
  43. postsynaptic cell
    receives action potential
  44. what are the two types of Synapses?
    • Electrical synapses
    • Chemical synapses
  45. ____ _____ involve direct cytoplasmic connections between the two cells formed by gap junctions
    • Electrical Synapses
    • spliced together
    • relatively rare in vertebrates
  46. ____ ____ have a synaptic cleft between the two cells
    Chemical synapses
  47. End of presynaptic cell contains synaptic vesicles packed with _______
    neurotransmitters. these travel between communicating cells
  48. Types of neurotransmitters
    • Acetylcholine
    • Amino acids
    • Biogenic amines
    • several others
  49. Acetylcholine
    • control skeletal muscle. crosses the synapse between a motor neuron and a muscle fiber.
    • Binds to a ligand gated receptor in the post synaptic membrane.
  50. Neuromuscular junction
    synapse between a motor neuron and a muscle fiber
  51. when Acetylcholine binds to a ligand-gated receptor, this produces a depolarization called an ___ ___ ___
    excitatory postsynaptic potential
  52. Acetylcholinesterase degrades ______ and causes muscle ______
    Acetylcholine ; relaxation
  53. Glutamate
    • amino acid
    • major excitatory neurotransmitter in the vertebrate CNS
  54. Glycine and GABA are ______ neurotransmitters
  55. When Glycine and or GABA open ligand-gated channes for Cl- the produce a ________ called an ____ ____ ____
    hyperpolarization ; inhibitory postsynaptic potential
  56. 3 Biogenic amines and their effects
    • Epinephrine (adrenaline) and Norepinephrine are responsible for the "fight or flight" response
    • Dopamine is used in some areas of the brain that control body movements.
    • Serotonin is involved in the regulation of sleep
  57. Substance P
    is released from sensory neurons activated by painful stimuli
  58. Intensity of pain perception depends on ______ and _____
    enkephalins ; endorphins
  59. _____ ____ ,a gas, causes smooth muscle ______
    Nitric oxide ; relaxation
Card Set:
2014-02-01 20:52:08
biology 43 systems

biology second chapter 43
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