ACTIVITY CH 12 1. The motor portion of the autonomic nervous system 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 neurons? a) mitochondria d) Golgi apparatus b) nucleus e) nucleolus c) Nissl body 3. This type of neuron has one dendrite and one axon emerging from the cell body. a) Multipolar neuron d) Purkinje cell b) Bipolar neuron e) Renshaw cell c) Unipolar neuron 4. Schwann’s cells begin to form myelin sheaths around axons 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 action potential. 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 neurotransmitter 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 dendrites. 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 synapse. 11. What factors limit neurogenesis in the CNS of adults? Neurogenesis in adults is limited by: 1) Inhibitory influences from neuroglia, mainly from oligodendrocytes, and 2) the absence of growth-stimulating cues present during fetal development 12. Describe four ways drugs can modify the effects of neurotransmitters. 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 membrane potential in excitable cells. The major factors that lead to creation of resting potential 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 depolarization. 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) nociceptor 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 node of Ranvier? 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 spinal cord? 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 retina of the eye, inner ear, 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 cerebellum? 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 synapses 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) axon terminal 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.