Chapter 12 Fundamentals of the Nervous System and the Nervous Tissue PDF

Chapter 12 Fundamentals of the Nervous System and Nervous Tissue 12.1 Multiple Choice Questions 1) Which of these is not a function of the nervous system? A) sensory input B) motor innervation to muscles or glands C) integration of motor and sensory information D) secreting hormones into the blood...

Chapter 12 Fundamentals of the Nervous System and Nervous Tissue 12.1 Multiple Choice Questions 1) Which of these is not a function of the nervous system? A) sensory input B) motor innervation to muscles or glands C) integration of motor and sensory information D) secreting hormones into the bloodstream to affect far-away organs Answer: D Section: 12.1 Book LO: 12.1 Global LO: G2 Bloom's Level: Remembering/Understanding 2) Which of the following is true regarding the basic divisions of the nervous system? A) The nerves in our arms and legs are part of the central nervous system. B) The brain and spinal cord are part of the peripheral nervous system. C) The central nervous system is in charge of integrating incoming sensory information with past experiences and dictating motor responses. D) The central nervous system includes the spinal nerves and cranial nerves. Answer: C Section: 12.1 Book LO: 12.2 Global LO: G2 Bloom's Level: Remembering/Understanding 3) Which of the following is not considered a special somatic sense? A) smell B) taste C) pain D) equilibrium Answer: C Section: 12.1 Book LO: 12.2 Global LO: G2 Bloom's Level: Remembering/Understanding 1 Copyright © 2020 Pearson Education, Inc. 4) The peripheral nerve fibers that measure the degree of stretch in the biceps brachii muscle and its tendons are classified as A) general somatic sensory. B) general somatic motor. C) special visceral sensory. D) general visceral motor. Answer: A Section: 12.1 Book LO: 12.2 Global LO: G2 Bloom's Level: Applying/Analyzing 5) An example of proprioception is A) the contraction of the triceps brachii. B) the contraction of pharyngeal arch muscles used in chewing. C) sensing a feather touch the skin. D) the sensation you feel during a wake-up stretch. Answer: D Section: 12.1 Book LO: 12.2 Global LO: G2 Bloom's Level: Applying/Analyzing 6) A somatic motor neuron carries A) information that signals muscle contraction in the organs in the ventral cavity. B) information, such as pain, from the viscera in the ventral cavity to the CNS. C) motor commands to the skeletal musculature. D) information from the skin to the CNS. Answer: C Section: 12.1 Book LO: 12.2 Global LO: G1 Bloom's Level: Remembering/Understanding 7) The peripheral nerve fibers that speed up the movement of the digestive tract are classified as A) general visceral sensory (afferent). B) special visceral sensory. C) general visceral motor (efferent). D) special somatic motor. Answer: C Section: 12.1 Book LO: 12.2 Global LO: G2 Bloom's Level: Remembering/Understanding 2 Copyright © 2020 Pearson Education, Inc. 8) A nerve cell is the same as a A) nerve. B) nerve fiber. C) neurilemmocyte. D) neuron. Answer: D Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 9) Which of the following is not a characteristic of neurons? A) longevity B) inability to divide C) high metabolic rate D) ability to survive without oxygen Answer: D Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 3 Copyright © 2020 Pearson Education, Inc. Use the diagram pictured above to answer the following questions. 10) Identify the letter that indicates the region of a neuron from which the axon leaves the cell body. A) A B) B C) C D) D E) E Answer: B Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 11) Identify the letter that indicates the region of a neuron where neurotransmitters are released. A) A B) B C) C D) D E) E Answer: E Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 4 Copyright © 2020 Pearson Education, Inc. 12) Identify the letter that indicates a Schwann cell. A) A B) B C) C D) D E) E Answer: C Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 13) Identify the letter that indicates the gaps between Schwann cells that are known as myelin sheath gaps (nodes of Ranvier). A) A B) B C) C D) D E) E Answer: D Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 14) Axodendritic synapses occur between letter "E" on the diagram and this region on a proximal neuron. A) A B) B C) C D) D E) E Answer: A Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 5 Copyright © 2020 Pearson Education, Inc. 15) This region of the neuron contains a single nucleus surrounded by cytoplasm. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: D Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 16) This region of a neuron contains chromatophilic substance or Nissl bodies. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: D Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 17) Neurofibrils A) form synapses with axons of postsynaptic neurons. B) help circulate cerebrospinal fluid. C) prevent the neuron from being pulled apart when subjected to tensile forces. D) receive incoming stimuli and pass the signal toward the cell body. Answer: C Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 18) Ganglia represent A) groups of axons in the PNS. B) groups of dendrites in the CNS. C) groups of neuron cell bodies in the PNS. D) groups of synapses in the CNS. Answer: C Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 6 Copyright © 2020 Pearson Education, Inc.  7 Copyright © 2020 Pearson Education, Inc. 19) Of the following, which is the only structure that is in the PNS, as opposed to the CNS? A) a tract B) white matter C) a ganglion D) gray matter Answer: C Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 20) This region of a neuron is characterized by numerous, short cytoplasmic extensions and is often referred to as receiving regions. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: E Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 21) All of the following are characteristics of dendrites except that they A) are more extensive branching than axons. B) always conduct action potentials. C) conduct signals toward the cell body. D) typically occur as more than one per cell. Answer: B Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Applying/Analyzing 22) This neuronal region transmits electrical impulses away from the cell body. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: C Section: 12.2 Book LO: 12.3 Global LO: G2 8 Copyright © 2020 Pearson Education, Inc. Bloom's Level: Remembering/Understanding 23) Which of the following statements about an axon is false? A) It is also referred to as a nerve fiber. B) It has branches. C) It carries nerve impulses toward the cell body. D) It has a uniform diameter. Answer: C Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 24) This tends to be the longest cytoplasmic projection from a neuron. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: C Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 25) In this part of a neuron, neurofilaments, actin microfilaments, and microtubules are particularly abundant, providing structural support and a transport network. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: C Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 26) Action potentials travel along the A) axon membrane. B) dendrite membrane. C) cell body. D) myelin. Answer: A Section: 12.2 9 Copyright © 2020 Pearson Education, Inc. Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 27) This part of the neuron may have branching collaterals. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: C Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 28) Mitochondria are particularly abundant here. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: B Section: 12.2 Book LO: 12.3 Global LO: G1 Bloom's Level: Remembering/Understanding 29) This is the site of communication between neurons. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: A Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Remembering/Understanding 30) Most synapses transmit communicating signals using A) chemical signaling molecules-neurotransmitters. B) electrical impulses travelling through gap junctions. C) physical contact between adjacent neurons. D) chemical signaling molecules released from neuroglia. 10 Copyright © 2020 Pearson Education, Inc. Answer: A Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Remembering/Understanding 31) In an axodendritic synapse, the region of the postsynaptic neuron that binds the released neurotransmitter is the A) synapse. B) axon terminal. C) axon. D) cell body. E) dendrite. Answer: E Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Applying/Analyzing 32) The ________ of a presynaptic neuron associates with the dendrite of a postsynaptic neuron. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: B Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Remembering/Understanding 33) An axosomatic synapse occurs between the axon terminals of one neuron and the ________ of a proximal neuron. A) synapse B) axon terminal C) axon D) cell body E) dendrite Answer: D Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Remembering/Understanding 11 Copyright © 2020 Pearson Education, Inc. 34) The chemical substance that is released at axon terminals is called a A) hormone. B) neurotransmitter. C) synaptic vesicle. D) Nissl body. Answer: B Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Remembering/Understanding 35) Vesicles containing neurotransmitters are located in A) a synaptic cleft. B) axon terminals. C) the postsynaptic region of dendrites. D) the nodes of Ranvier. Answer: B Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Remembering/Understanding 36) Which of the following is the correct path an impulse takes across a synapse? A) axon of postsynaptic neuron, dendrite of presynaptic neuron, synaptic cleft B) dendrite of presynaptic neuron, synaptic cleft, axon of postsynaptic neuron C) axon of presynaptic neuron, synaptic cleft, dendrite of postsynaptic neuron D) synaptic cleft, dendrite of postsynaptic neuron, axon of presynaptic neuron Answer: C Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Applying/Analyzing 37) Which of the following statements about neurotransmitters is false? A) They alter the charge of the postsynaptic neuron membrane. B) They are waves of positive charges that travel down axons. C) They are released from synaptic vesicles. D) They diffuse across the synaptic cleft. Answer: B Section: 12.2 Book LO: 12.4 Global LO: G2 Bloom's Level: Remembering/Understanding 12 Copyright © 2020 Pearson Education, Inc. 38) The majority of neurons in the body are A) multipolar. B) bipolar. C) unipolar. D) pseudounipolar. Answer: A Section: 12.2 Book LO: 12.5 Global LO: G2 Bloom's Level: Remembering/Understanding 39) Which relatively rare type of neuron has two processes extending from opposite sides of the cell body? A) bipolar B) multipolar C) pseudounipolar D) unipolar Answer: A Section: 12.2 Book LO: 12.5 Global LO: G2 Bloom's Level: Remembering/Understanding 40) Which of the following statements concerning sensory neurons is incorrect? A) Most are pseudounipolar. B) Most have their cell bodies in ganglia outside the CNS. C) They have peripheral and central processes. D) They contain only dendrites. Answer: D Section: 12.2 Book LO: 12.5 Global LO: G2 Bloom's Level: Remembering/Understanding 41) Interneurons are found A) only in the visceral nervous system. B) only in the CNS. C) only in the PNS. D) only in the autonomic nervous system. Answer: B Section: 12.2 Book LO: 12.5 Global LO: G2 Bloom's Level: Remembering/Understanding 13 Copyright © 2020 Pearson Education, Inc. Use the diagrams above to answer the following questions. 42) Identify which diagram represents a microglial cell. A) A B) B C) C D) D E) E Answer: C Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 43) Identify which diagram represents a cell that produces a myelin sheath in the central nervous system. A) A B) B C) C D) D E) E Answer: E Section: 12.2 Book LO: 12.6 Global LO: G2 14 Copyright © 2020 Pearson Education, Inc. Bloom's Level: Applying/Analyzing 44) Identify which letter represents the most abundant category of glial cells in the CNS. A) A B) B C) C D) D E) E Answer: B Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 45) Identify which letter represents an oligodendrocyte. A) A B) B C) C D) D E) E Answer: E Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 46) Identify which diagram represents cells that produce and circulate cerebrospinal fluid. A) A B) B C) C D) D E) E Answer: D Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 47) Astrocytes perform all of the following functions except A) regulating levels of neurotransmitters around the neurons B) controlling ion levels in the environment around neurons C) help with synapse formation in the developing nervous system D) produce cerebrospinal fluid Answer: D Section: 12.2 15 Copyright © 2020 Pearson Education, Inc. Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 48) Which cells are the macrophages of the CNS? A) ependymal cells B) microglial cells C) satellite cells D) Schwann cells Answer: B Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 49) These glial cells arise from embryonic white blood cells. A) ependymal cells B) microglia C) oligodendrocytes D) satellite cells Answer: B Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Applying/Analyzing 50) Ciliated neuroglial cells that form an epithelium and play an active role in forming and moving cerebrospinal fluid are A) ependymal cells. B) Schwann cells. C) oligodendrocytes. D) astrocytes. Answer: A Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 51) These glial cells surround the cell bodies of sensory neurons within ganglia of the PNS. A) astrocytes B) microglia C) satellite cells D) Schwann cells Answer: C Section: 12.2 16 Copyright © 2020 Pearson Education, Inc. Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 17 Copyright © 2020 Pearson Education, Inc. 52) Most tumors in the brain originate from glial cells, but not neurons. What characteristic of glial cells make them the most likely source of tumors in the brain? A) Glial cells are able to divide, while neurons are not. B) Glial cells naturally release a tumor-promoting factor. C) Glial cells carry a neuronal signal, making them vulnerable to abnormal replication. D) Glial cells are easily damaged by the electrical signal carried on the neurons. Answer: A Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 53) Which cells provide the myelin sheath for neurons in the CNS? A) Schwann cells B) astrocytes C) microglial cells D) oligodendrocyctes Answer: D Section: 12.2 Book LO: 12.7 Global LO: G2 Bloom's Level: Remembering/Understanding 54) Which cells provide the myelin sheath for neurons in the PNS? A) astrocytes B) microglial cells C) Schwann cells D) oligodendrocytes Answer: C Section: 12.2 Book LO: 12.7 Global LO: G2 Bloom's Level: Remembering/Understanding 55) Myelin on axons functions to A) make the axons live longer. B) store nutrients (fat) for use by the neurons. C) cover nodes of Ranvier. D) speed the rate of impulse conduction and insulate neighboring axons from one another. Answer: D Section: 12.2 Book LO: 12.7 Global LO: G2 Bloom's Level: Remembering/Understanding 18 Copyright © 2020 Pearson Education, Inc. 56) A node of Ranvier (myelin sheath gap) A) occurs only in ganglia. B) is one segment of the myelin sheath. C) occurs in the PNS but not in the CNS. D) is a bare region of axonal membrane in myelinated axons only. Answer: D Section: 12.2 Book LO: 12.7 Global LO: G2 Bloom's Level: Remembering/Understanding 57) Nonmyelinated axons A) are thicker than myelinated axons. B) are not associated with any Schwann cells. C) conduct impulses more slowly than myelinated axons. D) occur in the PNS, but not in the CNS. Answer: C Section: 12.2 Book LO: 12.7 Global LO: G2 Bloom's Level: Applying/Analyzing 58) The difference between myelinated and unmyelinated axons in the PNS is that A) Schwann cells are not associated with unmyelinated axons. B) Schwann cells form more widely spaced nodes of Ranvier in unmyelinated axons. C) Schwann cells simultaneously surround multiple axons in myelinated axons. D) Schwann cells wrap around myelinated axons in concentric layers. Answer: D Section: 12.2 Book LO: 12.7 Global LO: G2 Bloom's Level: Applying/Analyzing 59) The type of axon that conducts impulses most slowly is A) thick, myelinated. B) thick, unmyelinated. C) thin, myelinated. D) thin, unmyelinated. Answer: D Section: 12.2 Book LO: 12.7 Global LO: G2 Bloom's Level: Remembering/Understanding 19 Copyright © 2020 Pearson Education, Inc. 60) Gray matter in the CNS contains all of the following except A) neuron cell bodies. B) neuroglia. C) dendrites. D) fiber tracts. Answer: D Section: 12.3 Book LO: 12.8 Global LO: G2 Bloom's Level: Remembering/Understanding 61) In the spinal cord, the cell bodies of most interneurons lie in A) sensory ganglia. B) the PNS. C) the dorsal half of the gray matter. D) the ventral half of the white matter. Answer: C Section: 12.3 Book LO: 12.8 Global LO: G2 Bloom's Level: Remembering/Understanding 62) White matter represents A) aggregations of neuron cell bodies in the brain. B) aggregations of neuron cell bodies in the spinal cord. C) myelinated axons traveling together in the CNS. D) dendrites traveling together in the ANS. Answer: C Section: 12.3 Book LO: 12.8 Global LO: G2 Bloom's Level: Remembering/Understanding 63) Which of the following most immediately encases the smallest component of a nerve? A) endoneurium B) epineurium C) fascicle D) perineurium Answer: A Section: 12.3 Book LO: 12.9 Global LO: G2 Bloom's Level: Remembering/Understanding 20 Copyright © 2020 Pearson Education, Inc. 64) The covering of a fascicle within a nerve is the A) endoneurium. B) perineurium. C) ectoneurium. D) epineurium. Answer: B Section: 12.3 Book LO: 12.9 Global LO: G2 Bloom's Level: Remembering/Understanding 65) The entire nerve is surrounded by a tough fibrous sheath called the A) endoneurium. B) perineurium. C) ectoneurium. D) epineurium. Answer: D Section: 12.3 Book LO: 12.9 Global LO: G2 Bloom's Level: Remembering/Understanding 66) Which term is correctly matched with its definition? A) neuron — collection of axons in the PNS B) nerve fiber — a long axon C) nerve — a nerve cell D) neuron — a long axon Answer: B Section: 12.3 Book LO: 12.9 Global LO: G2 Bloom's Level: Remembering/Understanding 67) Interneurons A) carry incoming information from sensory receptors to the CNS. B) carry outgoing motor information to effectors in the PNS. C) sense information from the stimulus in the periphery D) take in sensory information, direct it to specific CNS locations, and initiate the appropriate response Answer: D Section: 12.4 Book LO: 12.12 Global LO: G2 Bloom's Level: Remembering/Understanding 21 Copyright © 2020 Pearson Education, Inc. 68) Which of the following is the correct arrangement of a reflex arc? A) receptor, sensory neuron, integration center, motor neuron, effector B) integration center, receptor, sensory neuron, motor neuron, effector C) effector, sensory neuron, integration center, motor neuron, receptor D) receptor, motor neuron, integration center, effector, sensory neuron Answer: A Section: 12.4 Book LO: 12.11 Global LO: G2 Bloom's Level: Remembering/Understanding 69) When the doctor uses a reflex hammer on your patellar ligament and you experience a "knee jerk" this is an example of a A) polysynaptic withdrawal reflex B) monosynaptic stretch reflex C) monosynaptic withdrawal reflex D) polysynaptic stretch reflex Answer: B Section: 12.4 Book LO: 12.11 Global LO: G2 Bloom's Level: Remembering/Understanding 70) A man walking barefoot stepped on a piece of glass. His foot jerked upward in which type of reflex? A) somatic, polysynaptic withdrawal reflex B) visceral, monosynaptic stretch reflex C) somatic, monosynaptic withdrawal reflex D) visceral, polysynaptic withdrawal reflex Answer: A Section: 12.4 Book LO: 12.11 Global LO: G2 Bloom's Level: Remembering/Understanding 71) A monosynaptic reflex arc is an example of A) a converging circuit. B) parallel processing. C) a reverberating circuit. D) serial processing. Answer: D Section: 12.4 Book LO: 12.13 Global LO: G2 Bloom's Level: Applying/Analyzing 22 Copyright © 2020 Pearson Education, Inc.  23 Copyright © 2020 Pearson Education, Inc. 72) An axon collateral from one neuron that circles back and synapses with a previous neuron describes A) a converging circuit. B) parallel processing. C) a reverberating circuit. D) serial processing. Answer: C Section: 12.4 Book LO: 12.14 Global LO: G2 Bloom's Level: Applying/Analyzing 73) In MS, the immune system attacks and breaks down the myelin sheath surrounding CNS axons. What could be a consequence of this? A) Conduction along the axon would be disrupted, interfering with the function of the neuron. B) Conduction would be faster along the neuron without the myelin. C) The neuron would not be able to generate a new action potential. D) There would be no consequence, as myelin is not important to the function of the neuron. Answer: A Section: 12.5 Book LO: 12.15 Global LO: G2 Bloom's Level: Applying/Analyzing 74) Regeneration of peripheral axons requires A) construction of a collateral that branches from the point of damage. B) deposition of neurofilaments to bridge the gap between the original axon fragments. C) formation of a tube by Schwann cells to guide growth. D) migration of neural stem cells from the hippocampus. Answer: C Section: 12.5 Book LO: 12.16 Global LO: G2 Bloom's Level: Remembering/Understanding 75) Motor neurons arise primarily from the A) alar plate. B) basal plate. C) ependyma. D) neural crest. Answer: B Section: 12.6 Book LO: 12.17 Global LO: G2 Bloom's Level: Remembering/Understanding 24 Copyright © 2020 Pearson Education, Inc.  25 Copyright © 2020 Pearson Education, Inc. 76) Sensory neurons arise primarily from the A) neural crest. B) alar plate. C) basal plate. D) neural tube. Answer: A Section: 12.6 Book LO: 12.17 Global LO: G2 Bloom's Level: Remembering/Understanding 77) During embryo development, neurons that make "bad" connections A) are inhibited by chemicals released from astrocytes. B) are turned off by inhibitory synapses in reverberating circuits. C) develop collaterals that seek out appropriate target cells. D) die by apoptosis. Answer: D Section: 12.6 Book LO: 12.17 Global LO: G2 Bloom's Level: Remembering/Understanding 12.2 True/False Questions 1) The somatic motor subdivision of the peripheral nervous system is considered to be an involuntary nervous system. Answer: FALSE Section: 12.1 Book LO: 12.2 Global LO: G2 Bloom's Level: Remembering/Understanding 2) Special somatic senses have receptors that are located mostly in the head, including hearing and balance and vision. Answer: TRUE Section: 12.1 Book LO: 12.2 Global LO: G2 Bloom's Level: Applying/Analyzing 3) General visceral sensory impulses include pain, temperature, nausea, and hunger. Answer: TRUE Section: 12.1 Book LO: 12.2 Global LO: G2 26 Copyright © 2020 Pearson Education, Inc. Bloom's Level: Remembering/Understanding 4) A neuron is a collection of nerve fibers in the PNS. Answer: FALSE Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 5) All of the neuron's organelles are localized to the cell body. Answer: FALSE Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 6) Any long axon is called a nerve fiber. Answer: TRUE Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 7) Chromatophilic bodies are clusters of rough ER and free ribosomes that produce the large amount of proteins needed by a neuron. Answer: TRUE Section: 12.2 Book LO: 12.3 Global LO: G2 Bloom's Level: Remembering/Understanding 8) Most neurons in the body are multipolar neurons. Answer: TRUE Section: 12.2 Book LO: 12.5 Global LO: G1 Bloom's Level: Remembering/Understanding 9) Less than 15% of all neurons are interneurons. Answer: FALSE Section: 12.2 Book LO: 12.5 Global LO: G2 Bloom's Level: Remembering/Understanding 27 Copyright © 2020 Pearson Education, Inc. 10) Microglia are ciliated to help circulate cerebrospinal fluid (CSF). Answer: FALSE Section: 12.2 Book LO: 12.6 Global LO: G2 Bloom's Level: Remembering/Understanding 11) Oligodendrocytes and Schwann cells myelinate neurons within the peripheral nervous system. Answer: FALSE Section: 12.2 Book LO: 12.7 Global LO: G2 Bloom's Level: Remembering/Understanding 12) The supporting cells of the nervous system that surround and wrap neurons are derived from embryonic neuroepithelial cells from the ectoderm. Answer: TRUE Section: 12.6 Book LO: 12.6 & 12.17 Global LO: G2 Bloom's Level: Applying/Analyzing 13) The white matter is the site where neuron cell bodies are clustered. Answer: FALSE Section: 12.4 Book LO: 12.9 Global LO: G2 Bloom's Level: Remembering/Understanding 14) The PNS and CNS are structurally linked together within the gray matter of the CNS. Answer: TRUE Section: 12.4 Book LO: 12.10 Global LO: G2 Bloom's Level: Remembering/Understanding 15) In a converging circuit, one presynaptic neuron synapses with many other neurons. Answer: FALSE Section: 12.4 Book LO: 12.14 Global LO: G2 Bloom's Level: Remembering/Understanding 28 Copyright © 2020 Pearson Education, Inc. 12.3 Short Answer Questions 1) ________ components of the PNS regulate contraction of smooth and cardiac muscle. Answer: Visceral motor 2) Cytoplasm, organelles, and neurotransmitters move through the cytoplasm of the axon by a mechanism called ________. Answer: axonal transport 3) Neurotransmitters are found packaged inside ________ in the axon terminal. Answer: synaptic vesicles 4) Nearly all somatic sensory neurons are of this type, based on the classification of the type and number of processes. Answer: pseudounipolar 5) Nearly all motor neurons are of this type, based on the classification of the type and number of processes. Answer: multipolar 6) These neurons reside only in the CNS and connect motor and sensory neurons. Answer: interneurons, or association neurons 7) ________ are the neuroglial cells with cilia. Answer: Ependymal cells 8) ________ form the myelin sheaths in the brain and spinal cord. Answer: Oligodendrocytes 9) The ________ matter of the spinal cord forms a butterfly-shaped structure. Answer: gray 10) White matter is white in color because of ________. Answer: myelinated axons 11) The simplest of all reflexes, involving just two neurons, is the ________ reflex. Answer: monosynaptic 12) A ________ circuit occurs when many neurons synapse onto one neuron. Answer: converging 13) ________ processing occurs when information from a single neuron is sent along two or more pathways traveling in the same direction. Answer: Parallel 29 Copyright © 2020 Pearson Education, Inc. 14) ________ are chemicals that control the growth of newly forming neurons. Answer: Neurotrophins 15) ________ neurons develop from neural crest cells. Answer: Sensory 12.4 Essay Questions 1) Describe the myelin sheath. Answer: Schwann cells in the PNS and oligodendrocytes in the CNS produce the myelin sheath. These cells wrap around the larger axons of the body. They function as an insulating layer that prevents the electrical current from diminishing in strength as it travels the length of the axon This results in extremely efficient transmission of neuronal impulses to the target tissue. 2) Name four characteristics that distinguish neuroglial cells from neurons. Answer: Glial cells are smaller, they have a very darkly staining nucleus, they can divide throughout life, and they greatly outnumber neurons. 3) Describe layers of myelin and connective tissue surrounding a nerve. Answer: The axon is myelinated by Schwann cells, with each individual axon covered with a loose connective tissue layer called the endoneurium. Groups of these axons are found in bundles, called fascicles, surrounded by the perineurium. These fascicles are held together by an outer fibrous connective tissue layer — the epineurium, which collectively is the nerve. Embedded in the connective tissue layers are blood vessels which provide oxygen and nutrients to all of the cells enclosed by the epineurium. 4) Distinguish monosynaptic reflexes from polysynaptic reflexes. Answer: Monosynaptic reflexes involve a single sensory neuron, with the cell body in the dorsal root ganglion and the axon forming a synapse with the motor neuron in the ventral horn of the gray matter of the spinal cord. The axon of the motor neuron (somatic or visceral) exits the gray matter and directs the motor impulse towards skeletal muscle or glandular tissue. Polysynaptic reflexes have more than one synapse and include interneurons, which may be localized to the same level of the spinal cord but most commonly involve multiple synapses, and neural connections may run to other levels of the spinal cord, as well as to the brain. 5) Distinguish between converging, diverging, and reverberating neuronal circuits. Identify the role of axon collaterals and terminal branches in these circuits. Answer: In converging circuits, a single neuron receives stimuli from multiple neurons. The target neuron must integrate the multiple incoming signals. In diverging circuits, a single neuron synapses with multiple target cells through many terminal branches of its axon. In reverberating circuits, a postsynaptic neuron will branch, and its axon collateral will synapse with one of its presynaptic neurons and alter the activity of that neuron. 30 Copyright © 2020 Pearson Education, Inc.