Practice Questions on the Nervous System
Page 3

  1. Positively charged ions are known as _____________ while negatively charged ions are _________.
  2. On the inner surface of a resting neuron's cell membrane, there is an accumulation of __________________.
  3. In electrical terms, potential is synonymous with __________.
  4. An excitable cell is one that can quickly and dramatically change its membrane potential. 2 examples of excitable cells are ________ and _________.
  5. The typical neuron resting membrane potential measures approximately _______.
  6. A neuronal impulse may also be called a(n) ______________ which indicates that it is a "moving" region of "voltage change" that migrates along the neuronal cell membrane.
  7. There is a greater concentration of ______________ ions accumulating on the outer surface of resting neuronal membranes than on the inner surface.
  8. The 2 ways an ion may passively travel thru a membrane are through _____ channels and gated channels which are typically ________-gated or _________-gated.
  9. The Na+/K+ pump operates by pumping _______________ions out of the cell while pumping ________ ions into the cell.
  10. Voltage-gated ion channels open in response to changes in the ________.
  11. Neurotransmitters bind to specific _____________ on the neuronal cell surface. This binding will trigger the opening of ion channels that cause a temporary change in the local membrane potential. Such a transient, local change is called a ___________________.
  12. When cations flow into a neuron, the membrane potential becomes _____ positve and ________ negative.
  13. Voltage-gated sodium channels are triggered to open when the resting membrane potential reaches about ____________ which is referred to as the ___________ potential.
  14. A massive sodium influx causes ________________.
  15. _____________ is an example of a drug that blocks the opening of Na+ channels, thus blocking the initiation of neuronal action potentials.
  16. After the first phase of the action potential, the ____ channels become inactivated while the ____ channels begin to open. This occurs when the membrane potential reaches about +30mV. The opening of these channels results in K+ ________. This is known as _______________.
  17. The refractory period of an AP causes that region of the membrane to be ___________ to another stimulus. This ensures that APs migrate in only one direction, namely, away from the __________.
  18. Overall, 2 important factors drive the movement of Na+ and K+ across cell membranes. These are the _________ gradient and the __________ gradient.
  19. For any given neuron, all APs are of the same intensity. This is referred to as the ______________ principle. In order to alter the perceived intensity of a given stimulus, the _________ of APs is increased.
  20. APs travel fastest in axons that have a __________ diameter and are ___________. The fastest neuronal axon fibers are A type fibers which carry _________ and ___________ motor signals. The slowest fibers are the C-type fibers which are of _________ diameter and are ______________.
  21. At the axon terminals, voltage-gated _______ channels open in response to the arriving AP. This triggers ___________ to fuse with axon terminal membrane and release the __________ into the _______________.
  22. Most neurons in the CNS communicate with _________ of other neurons.
  23. The small extensions off the neuronal cell bodies that receive stimuli are the __________________.
  24. Small, variable-intensity, transient changes in membrane potential that move the potential closer to threshold are known as _______________. While small, variable-intensity, transient changes that move the potential farther from threshold are _________________.
  25. ___________ is a common inhibitory neurotransmitter in the CNS.
  26. Movement of Cl- into a neuron would make a neuron _________ likely to fire an AP.
  27. A sympathetic preganglionic fiber is (myelinated, unmyelinated), (short,long), and (cholinergic, adrenergic).
  28. From which segments of the spinal cord do sympathetic preganglionic neurons originate?
  29. True or False; Sympathetic ganglia are NOT paravertebral.
  30. Sympathetic postganglionic fibers are long, myelinated and adrenergic. (True or False)
  31. Norepinephrine is released by most postganglionic sympathetic neurons. Name the exceptions - i.e., the ones that release acetylcholine.
    For each of the following, indicate the branch of the efferent nervous system, the neurotransmitter, and all of the following effector organ responses. (No need to consider receptors in any ganglia.)

  32. Increased blood flow to skeletal muscles
  33. Decreased pupil diameter
  34. Skeletal muscle contraction
  35. Decreased heart rate
  36. Sweating
  37. Saliva secretion
  38. Increased intestinal secretions
  39. Decreased intestinal motility
  40. Decreased diameters of respiratory airways
  41. Consider the concept of dual innerveration and the fact that an ANS effector pathway has 2 neurons. If you administer atropine (a muscarinic antagonist) i.v. followed by a high dose of ACh, you see an increase in heart rate. Where is the ACh acting?
  42. You administer ACh to patient and observe the change in heart rate. You then administer hexamethonium (a nicotinic antagonist) followed by the same dose of ACh and observe no change in the original response to the ACh. Why not?
  43. As the frequency of action potentials on a preganglionic sympathetic nerve increases, the frequency of action potentials on a postganglionic nerve __________________.
  44. During a fight-or-flight response, the diameter of the pupil of the eye ________________.
  45. Parasympathetic activity causes the activity of the gastrointestinal organs to _______________.
  46. Chlorine entry into a cell as a result of binding of glycine will result in an...
  47. If a neuron synapses on a striated muscle, would it be myelinated?

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