Bio 93 Lecture 25

  1. What are neurons?
    nerve cells that transfer information within the body
  2. What are the two types of signals neurons use to communicate?
    electrical signals (long distance) and chemical signals (short distance)
  3. Define central nervous systems:
    the complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.
  4. Define the peripheral nervous system:
    the nervous system outside the brain and spinal cord.
  5. What is ganglia?
    simple clusters of neurons in which processing of information takes place
  6. Nervous systems process information in three stages:
    sensory input, integration, and motor input
  7. What is a synapse?
    a junction between an axon and another cell
  8. What does the synaptic terminal do?
    it passes information across the synapse in the form of chemical messengers called neurotransmitters
  9. What are neurotransmitters?
    chemical messengers
  10. What does an axon hillock do?
    joins the cell body to the axon
  11. Information is transmitted from a _____________ to a _____________ (give examples of each)
    presynaptic cell (a neuron), postsynaptic cell (a neuron, muscle cell, or gland cell)
  12. Most neurons are nourished or insulated by cells called:
    glia (most of the cells in the brain)
  13. Glia cells have numerous functions:
    • blood-brain barrier-protects the neurons
    • cerebral spinal fluid- cushions the brain
    • microglia- protects the nervous system from microorganisms
    • myelin sheath- protects axon
  14. Tumors arise from:
    uncontrolled cell division
  15. Tumors result in:
    mass of cells which can be malignant (cancerous) or benign (non-cancerous)
  16. Due to their structure, neurons:
    do not divide
  17. Most primary tumors are:
    gliomas or meningiomas
  18. Secondary tumors can arise from:
    malignant tumors originating in other regions of the body
  19. What maintains a resting potential of a neuron?
    ion pumps and ion channels
  20. What is membrane potential?
    a voltage across its plasma membrane
  21. What is the resting potential?
    the membrane potential of a neuron not sending signals
  22. In a mammalian neuron at resting potential, the concentration of ___ is greater inside the cell, while the concentration of ___ is greater outside the cell
    K+, Na+
  23. What do sodium potassium pumps use to maintain these K+ and Na+ gradients across the plasma membrane?
    energy of ATP
  24. What is a resting potential?
    the membrane potential of a resting neuron one that is not sending signals
  25. The opening of ________ in the plasma membrane converts chemical potential to electrical potential
    ion channels
  26. A neuron at ___________ contains many open K+ channels (K+ leak channels, not voltage-gated potassium channels) and fewer open Na+ channels; K+ diffuses out of the cell
    resting potential
  27. Neurons contain ______________ that open or close in response to stimuli
    voltage gated ion channels
  28. Leak Potassium channels:
    always open and helps set the resting potential
  29. Voltage gated potassium channel:
    important for restoring membrane potential following depolarisation. Opens slowly causing delayed efflux of potassium
  30. Voltage gated sodium channels:
    important for depolarising membrane (making more positive) during action potentials. Opens rapidly allowing influx of sodium
  31. Voltage gated calcium channels:
    Opens when membrane depolarises and lets calcium flow into cell. Important for synaptic release.
  32. What occurs in depolarization:
    • Gated Na+ channels open
    • Na+ diffuses into the cell
    • the membrane potential becomes less negative
  33. What is an action potential?
    nerve impulse or signal that carries information along the axon
  34. When does an action potential occur?
    when depolarization reaches threshold (-55mV)
  35. What is the resting potential?
    -70 mV
  36. The ______ of action potentials can reflect the strength of stimulus
    frequency
  37. The refractory period is:
    a result of a temporary inactivation of the Na+ channels
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jocelyn0399
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Bio 93 Lecture 25
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