A&P Chapter 19: Nerve Signaling

Question 1

1. Compared with the inside of the cell, the outside of most cell membranes is:
   a. positive.
   b. negative.
   c. equal.
   d. none of the above.

Answer 1

1. a. positive.
   p. 413

Chapter 19: Nerve Signaling

Question 2

Multiple Choice

2. The difference in electrical charge across a plasma membrane is called:
   a. depolarization.
   b. membrane potential.
   c. both a and b.
   d. none of the above.

Answer 2

2. b. membrane potential.
   p. 413

Chapter 19: Nerve Signaling

Question 3

Multiple Choice

3. A neuron’s resting membrane potential is:
   a. 70 mV.
   b. –70 mV.
   c. 30 mV.
   d. –30 mV.

Answer 3

3. b. –70 mV.
   p. 413

Chapter 19: Nerve Signaling

Question 4

4. Which of the following statements is true concerning the sodium-potassium pump?
   a. Three sodium ions are pumped out of the neuron for every two potassium ions pumped into the neuron.
   b. Two sodium ions are pumped out of the neuron for every three potassium ions pumped into the neuron.
   c. Three sodium ions are pumped out of the neuron for every three chloride ions pumped into the neuron.
   d. Three sodium ions are pumped out of the neuron for every three potassium ions pumped into the neuron.

Answer 4

4. a. Three sodium ions are pumped out of the neuron for every two potassium ions pumped into the neuron.
   p. 414

Chapter 19: Nerve Signaling

Question 5

5. ______ A membrane that exhibits a membrane potential is said to be polarized.

True or False

Answer 5

5. True
   p. 413

Chapter 19: Nerve Signaling

Question 6

6. ______ A slight shift away from the resting membrane potential in a specific region of the plasma membrane is often called a stimulus-gated channel.

True or False

Answer 6

6. False
   p. 414

Chapter 19: Nerve Signaling

Question 7

7. ______ Chlorine ions (Cl–) are the dominant extracellular cations.

True or False

Answer 7

7. False
   p. 414

Chapter 19: Nerve Signaling

Question 8

8. During a relative refractory period:
   a. an action potential is impossible.
   b. an action potential is possible only in response to a very strong stimuli.
   c. an action potential is occurring.
   d. none of the above.

Answer 8

8. b. an action potential is possible only in response to a very strong stimuli.
   p. 417

Chapter 19: Nerve Signaling

Question 9

9. Voltage-gated channels are:
   a. membrane channels that close during voltage fluctuations.
   b. ion channels that open in response to voltage fluctuations.
   c. membrane channels that are altered from an extremely high stimulus.
   d. none of the above.

Answer 9

9. b. ion channels that open in response to voltage fluctuations.
   p. 415

Chapter 19: Nerve Signaling

Question 10

10. When current leaps across an insulating myelin sheath from node of Ranvier to node of Ranvier, the type of impulse conduction is:
    a. repolarization.
    b. refraction.
    c. saltatory conduction.
    d. diffusion.

Answer 10

10. c. saltatory conduction.
    p. 418

Chapter 19: Nerve Signaling

Question 11

11. The larger the diameter of a nerve fiber:
    a. the slower the speed of conduction.
    b. the faster the speed of conduction.
    c. Fiber diameter does not influence speed of conduction.
    d. the more the speed fluctuates.

Answer 11

11. b. the faster the speed of conduction.
    p. 418

Chapter 19: Nerve Signaling

Question 12

12. ______ Action potential and nerve impulse are synonymous.

True or False

Answer 12

12. True
    p. 415

Chapter 19: Nerve Signaling

Question 13

13. ______ When repolarization has occurred, an impulse cannot be conducted.

True or False

Answer 13

13. False
    p. 417

Chapter 19: Nerve Signaling

Question 14

14. ______ The action potential is an all-or-none response.

True or False

Answer 14

14. True
    p. 418

Chapter 19: Nerve Signaling

Question 15

15. ______ Many anesthetics function by inhibiting the opening of sodium channels and thus blocking the initiation and conduction of nerve impulses.

True or False

Answer 15

15. True
    p. 419

Chapter 19: Nerve Signaling

Question 16

16. Which of the following structures is not a main component of a chemical synapse?
    a. synaptic knob
    b. synaptic cleft
    c. synaptic process
    d. plasma membrane of postsynaptic neuron

Answer 16

16. c. synaptic process
    p. 419

Chapter 19: Nerve Signaling

Question 17

17. A synaptic knob is located on the:
    a. synaptic cleft.
    b. axon.
    c. dendrite.
    d. cell body.

Answer 17

17. b. axon.
    p. 419

Chapter 19: Nerve Signaling

Question 18

18. Which of the following is true of spatial summation?
    a. Neurotransmitters released simultaneously from several presynaptic knobs converge on one postsynaptic neuron.
    b. Simultaneous stimulation of more than one postsynaptic neuron occurs.
    c. Impulses are fired in a rapid succession by the same neuron.
    d. Speed of impulse transmission is increased when several neurotransmitters are released.

Answer 18

18. a. Neurotransmitters released simultaneously from several presynaptic knobs converge on one postsynaptic neuron.
    p. 422

Chapter 19: Nerve Signaling

Question 19

19. ______ In an adult, the nervous system is replete with both electrical synapses and chemical synapses.

True or False

Answer 19

19. False
    p. 419

Chapter 19: Nerve Signaling

Question 20

20. ______ Rapid-succession stimulation of a postsynaptic neuron by a synaptic knob can have a cumulative effect over time that can result in an action potential.

True or False

Answer 20

20. True
    p. 423

Chapter 19: Nerve Signaling

Question 21

21. ______ Ca++ ions cause the release of neurotransmitters across the synaptic cleft.

True or False

Answer 21

21. True
    p. 421

Chapter 19: Nerve Signaling

Question 22

22. Neurotransmitters are released in a synapse and bind to:
    a. presynaptic terminals.
    b. the synaptic cleft.
    c. the base of the axon.
    d. receptors on the postsynaptic terminal.

Answer 22

22. d. receptors on the postsynaptic terminal.
    p. 424

Chapter 19: Nerve Signaling

Question 23

23. The main chemical classes of neurotransmitters include all of the following except:
    a. acetylcholine.
    b. norepinephrine.
    c. amino acids.
    d. amines.

Answer 23

23. b. norepinephrine.
    p. 425

Chapter 19: Nerve Signaling

Question 24

24. Which of the following is not an example of an amine neurotransmitter?
    a. serotonin
    b. histamine
    c. glycine
    d. dopamine

Answer 24

24. c. glycine
    p. 425

Chapter 19: Nerve Signaling

Question 25

25. Severe depression can be caused by a deficit in which of the following neurotransmitters? a. acetylcholine b. amino acids c. amines d. neuropeptides

Answer 25

25. c. amines p. 428 Chapter 19: Nerve Signaling

Question 26

26. Which of the following is not a catecholamine? a. epinephrine b. norepinephrine c. dopamine d. serotonin

Answer 26

26. d. serotonin p. 425 Chapter 19: Nerve Signaling

Question 27

27. ______ Many biologists now believe that neuropeptides are the most common neurotransmitters in the CNS. True or False

Answer 27

27. False p. 428 Chapter 19: Nerve Signaling

Question 28

28. ______ Cocaine produces a temporary feeling of well-being by blocking the uptake of dopamine. True or False

Answer 28

28. True p. 428 Chapter 19: Nerve Signaling

Question 29

34. _______ Multiple sclerosis is a myelin disorder. True or False

Answer 29

34. True p. 431 Chapter 19: Nerve Signaling

Question 30

35. ______ Physical injury, causing nerve damage, can cause local or widespread loss of sensation and/or motor control. True or False

Answer 30

35. True p. 431 Chapter 19: Nerve Signaling

Question 31

36. _______ Nerve conduction does not occur due to fluctuations in the concentration of ions. True or False

Answer 31

36. False p. 431 Chapter 19: Nerve Signaling

Question 32

37. _______ Myasthenia gravis is a bacterial disorder. True or False

Answer 32

37. False p. 431 Chapter 19: Nerve Signaling

Question 33

38. ______ Parkinson disease is a failure to release adequate dopamine at the synapse of certain motor pathways. True or False

Answer 33

38. True p. 431 Chapter 19: Nerve Signaling

Question 34

39. Tracey was having a root canal procedure. Her dentist assured her that he would give her an anesthetic such as Marcaine that would keep her pain free the entire time. How does Marcaine prevent pain? Applying What You Know!

Answer 34

39. Marcaine, procaine, and similar drugs produce anesthesia by inhibiting the opening of the sodium channels and thus blocking the initiation and conduction of nerve impulses. Chapter 19: Nerve Signaling

Question 35

40. Susan was a cocaine abuser. Explain how the temporary feeling of well-being is achieved and the risk that abusing cocaine can be to the body. Applying What You Know!

Answer 35

40. Cocaine, which is often used in medical practice as a local anesthetic, produces a temporary feeling of well-being in cocaine abusers by similarly blocking the uptake of dopamine. Unfortunately, cocaine and similar drugs can also adversely affect blood flow and heart function when taken in large amounts—leading to death in some individuals. Chapter 19: Nerve Signaling

Question 36

41. A synaptic knob is a tiny bulge at the end of the (presynaptic or postsynaptic) neuron’s axon.

Answer 36

41. presynaptic p. 420 Chapter 19: Nerve Signaling

Question 37

42. Acetylcholine is an example of a (neurotransmitter or protein molecule receptor).

Answer 37

42. neurotransmitter p. 425 Chapter 19: Nerve Signaling

Question 38

43. Neurotransmitters are chemicals that allow neurons to (communicate or reproduce) with one another.

Answer 38

43. communicate p. 424 Chapter 19: Nerve Signaling

Question 39

44. Neurotransmitters are distributed (randomly or specifically) into groups of neurons.

Answer 39

44. specifically p. 424 Chapter 19: Nerve Signaling

Question 40

45. Endorphins and enkephalins are neurotransmitters that inhibit conduction of (fear or pain).

Answer 40

45. pain p. 429 Chapter 19: Nerve Signaling

Question 41

46. A synonym commonly used for action potential is (nerve impulse or depolarization).

Answer 41

46. nerve impulse p. 415 Chapter 19: Nerve Signaling

Question 42

47. In myelinated fibers, action potentials in the membrane occur only at the nodes of Ranvier. This type of impulse conduction is called (saltatory conduction or postsynaptic conduction).

Answer 42

47. saltatory conduction p. 418 Chapter 19: Nerve Signaling

Question 43

48. A membrane that exhibits a membrane potential is said to be (polarized or myelinated)

Answer 43

48. polarized p. 413 Chapter 19: Nerve Signaling

Question 44

59. _______ The function of a neurotransmitter is determined by the postsynaptic receptor. True or False

Answer 44

59. True p. 424 Chapter 19: Nerve Signaling

Question 45

60. ________ Neurotrophins stimulate neuron development but also can act as neurotransmitters or neuromodulators. True or False

Answer 45

60. True p. 429 Chapter 19: Nerve Signaling