ACTIVITY CH 12

1. The motor portion of the autonomic can be divided into a) somatic and sympathetic divisions. d) sympathetic and parasympathetic divisions. b) somatic and parasympathetic divisions. e) voluntary and involuntary divisions. c) enteric and somatic divisions.

2. Which of following organelles is a common site of protein synthesis in ? a) mitochondria d) Golgi apparatus b) nucleus e) nucleolus c)

3. This type of has one and one emerging from the cell body. a) d) b) e) c)

4. Schwann’s cells begin to form sheaths around in the peripheral nervous system a) when neurons are injured. b) during fetal development. c) after birth. d) only in response to electrical stimulation by neuroglial cells. e) during the early onset of Alzheimer’s disease.

5. A depolarizing graded potential a) makes the membrane more polarized. d) is the last part of an . b) makes the membrane less polarized. e) is seen when the cell approaches threshold. c) is considered a type of action potential.

6. When a depolarizing graded potential makes the axon membrane depolarize to threshold, a) ligand-gated Ca+2 channels close rapidly. d) voltage-gated Na+ channels open rapidly. b) voltage-gated Ca+2 channels open rapidly. e) none of these choices occur. c) ligand-gated Na+ channels close rapidly.

7. During this period, a second action potential can only be initiated by a larger than normal stimulus a) Latent period d) All of these choices b) Absolute refractory period e) None of these choices c) Relative refractory period

8. Diffusion, enzymatic degradation, and uptake by cells are all ways to a) remove a d) inhibit a presynaptic potential b) stop a spatial summation e) excite a presynaptic potential c) continue a temporal summation

9. When the summed total of postsynaptic potentials rises above threshold, creation of action potentials occurs a) in the synaptic cleft. d) in the neuron nucleus. b) in the . e) in the neuroplasm. c) at the trigger zone.

10. Plasticity means a) ability to regenerate after being damaged. d) ability to change based on experience. b) sending a signal through a converging circuit. e) ability to stretch and recoil without damage. c) signal transmission at a .

11. What factors limit neurogenesis in the CNS of adults? Neurogenesis in adults is limited by: 1) Inhibitory influences from neuroglia, mainly from , and 2) the absence of growth-stimulating cues present during fetal development

12. Describe four ways drugs can modify the effects of . Drugs can modify neurotransmitter effects by: 1) stimulating or inhibiting their synthesis, 2) enhancing or blocking their release, 3) activating or blocking their receptor, and 4) stimulating or inhibiting their removal.

13. List the three ways that neurotransmitters can be removed from a synapse. Neurotransmitters can be removed by: 1) diffusion, 2) enzymatic degradation or 3) uptake by cells.

14. List the three major factors that contribute to the creation of the resting in excitable cells. The major factors that lead to creation of are: 1) unequal distribution of ions across the plasma membrane, 2) inability of most anions to leave the cell, and 3) the electrogenic nature of the Na+,K+ -ATPase.

15. Briefly describe the events that occur during the depolarizing phase of an action potential. Voltage-gated Na+ channels open rapidly allowing Na+ to rush into the cell driven by both the electrical and chemical gradient. The inward rush of Na+ causes the membrane potential to become less negative, resulting in .

16. Which part of the diagram is considered nerve fiber? a) A b) D c) I d) Both A and D e) All of these choices make up the nerve fiber

17. This part of the neuron contains the nucleus and Nissl bodies. a) A b) B c) C d) E e) Both A and B

18. This part of a neuron contains the nucleus and cytoplasm of the Schwann’s cell that has formed a myelin sheath around the axon. a) C b) D c) E d) F e) G

19. In the diagram, where are axon terminals? a) F b) G c) H d) I e) None of these choices

20. Which of the neurons is considered to be a bipolar neuron? a) A b) B c) C d) All of the neurons. e) None of the neurons.

21. What specific type of unipolar neuron is shown in the diagram labeled B? a) Type I cutaneous mechanoreceptor (Merkel disc) b) Corpuscle of touch (Meissner corpuscle) c) Lamellated (Pacinian) corpuscle d) e) Purkinje cell

22. This structure electrically insulates the axon of a neuron to increase the speed of nerve impulse conduction. a) A b) B c) C d) D e) E

23. In the diagram, where is a ? a) A b) B c) C d) D e) E

24. In the CNS, this structure is produced by oligodendrocytes. a) A b) B c) C d) D e) E

25. Which of the following types of neurons is the most common type of neuron found in the brain and ? a) bipolar neuron d) nonpolar neuron b) multipolar neuron e) pseudounipolar c) unipolar neuron

26. Which of the following types of neurons have one axon and one dendrite emerging from the cell body and are found in the of the eye, inner , and olfactory region of the brain? a) bipolar neuron d) nonpolar neuron b) multipolar neuron e) pseudounipolar c) unipolar neuron

27. Which of the following types of neurons is exclusively found in the ? a) bipolar neuron d) unipolar neuron b) multipolar neuron e) pyramidal cells c) Purkinje cells

28. Which of the diagrams in the figure represents a ligand-gated channel? a) A b) B c) C d) D

29. Which of these types of channels is involved in leaking sodium and potassium ions across the membrane in order to establish the resting potential of a cell? a) A b) B c) C d) D

30. Which of the channels shown in the figure opens and closes randomly? a) A b) B c) C d) D e) All of these choices

31. What is the structural classification of the neuron labeled A? a) bipolar neuron b) multipolar neuron c) unipolar neuron d) nonpolar neuron e) pseudounipolar

32. What is the structural classification of the neuron labeled B? a) bipolar neuron b) multipolar neuron c) unipolar neuron d) nonpolar neuron e) pseudounipolar

33. Which diagram represents a reverberating circuit? a) A c) C b) B d) D

34. Which of the types of circuits is commonly used to send sensory signals to multiple areas of the brain? a) A c) C b) B d) D

35. Which type of circuit is used to lengthen the output signal in physiological processes like regulation of the breathing pattern? a) A c) C b) B d) D

36. Which type of circuit is involved in solving mathematical problems? a) A c) C b) B d) D

37. Which of the following neurotransmitters are used in virtually all of the inhibitory found in the spinal cord? a) gamma aminobutyric acid (GABA) and acetylcholine b) gamma aminobutyric acid (GABA) and glycine c) epinephrine and norepinephrine d) serotonin and melatonin e) glutamate and aspartate

38. Which type of depression results in an individual with a manic-depressive illness. a) major depression. d) seasonal affective disorder. b) dysthymia. e) all of these disorders. c) bipolar disorder.

39. Which of the following structures is labeled A in the diagram? a) d) peripheral process b) trigger zone e) dendrites c) cell body

40. Which of the following structures is labeled B in the diagram? a) axon terminal d) peripheral process b) trigger zone e) dendrites c) cell body

41. Which of the following structures is labeled C in the diagram? a) axon terminal d) peripheral process b) trigger zone e) dendrites c) cell body

42. Which of the following structures is labeled D in the diagram? a) axon terminal d) peripheral process b) trigger zone e) dendrites c) cell body

43. Which of the following structures is labeled E in the diagram? a) axon terminal d) axon b) trigger zone e) dendrites c) cell body

44. Name the type of membrane channel that opens in response to touch, pressure, vibration, or tissue stretching and is found in the auditory receptors of the ear, and in touch and pressure receptors in the skin. a) leakage channel d) voltage-gated channels b) ligand-gated channels e) temperature-sensitive channel c) mechanically gated channels

45. Wallerian degeneration refers to a) degeneration of the proximal end of axon and myelin sheath after neural injury. b) degeneration of the distal end of axon and myelin sheath after neural injury. c) break of Nissl bodies after neural injury. d) plasticity of neuron. e) none of these choices

46. Describe the difference between spatial and temporal summation in a postsynaptic neuron. Spatial summation is summation of postsynaptic potentials in response to stimuli that occur at different locations in the membrane of a postsynaptic cell at the same time. This typically occurs when multiple presynaptic neurons synapse with one postsynaptic neuron and fire simultaneously. Temporal summation is summation of postsynaptic potentials in response to stimuli that occur at the same location in the membrane of the postsynaptic cell but at different times. This typically occurs when one presynaptic neuron fires in rapid succession leading to a summing of the resulting EPSPs, which then triggers the generation of action potentials in the postsynaptic neuron as it moves above threshold

47. which of the following types of electrical signals allow rapid long-distance communication within the nervous system? a) resting potential d) graded potential b) nerve action potential e) long-term potentiation c) muscle action potential

48. Which of the labeled cells in the figure is NOT a neuroglial cell? a) A d) D b) B e) F c) C

49. Which of the labeled cells in the diagram is a neuroglial cell that forms and maintains the myelin sheath around CNS axons? a) A d) D b) B e) F c) C

50. Which of the labeled cells in the diagram is a neuroglial cell that forms and maintains the myelin sheath around CNS axons? a) A d) D b) B e) F c) C

51. Which of the labeled cells in the diagram is a neuroglial cell that removes debris and acts as a phagocyte? a) A d) D b) B e) F c) C

52. Which of the labeled cells in the diagram is a neuroglial cell that produces and assists in the circulation of cerebrospinal fluid? a) A d) D b) B e) F c) C

53. In an action potential, the current that flows down the axon of a neuron is generated by the movement of _____ across the membrane. a) electrons d) free radicals b) protons e) neutrons c) ions

54. In temporal summation, a single presynaptic neuron stimulates the creation of action potentials in a postsynaptic neuron when it a) stops firing long enough to allow the postsynaptic neuron to recover. b) fires at a fast enough rate that the sum of EPSPs in the postsynaptic neuron moves above threshold. c) fires at a steady rate that allows the postsynaptic neuron to return to resting potential. d) recruits other presynaptic neurons to begin to fire. e) runs out of neurotransmitter.