Which Neuron Would Activate to a Muscle

SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Figure 11.1 Using Figure 11.1, match the following: 1) Which neuron would activate to a muscle? Answer: A 2) Which neuron would be found in the retina of the eye? Answer: B 3) Which neuron is a sensory neuron found in a reflex arc? Answer: C 4) Which neuron is never myelinated? Answer: B 1 5) Which neuron is typically involved in the special senses of sight and smell? Answer: B 6) In a reflex arc, which neuron has its cell body inside the spinal cord? Answer: A 7) Which neuron is common only in dorsal root ganglia of the spinal cord and sensory ganglia of cranial nerves? Answer: C 8) Which is by far the most common neuron type? Answer: A Figure 11.2 Using Figure 11.2, match the following: 9) Ion channel. Answer: E 10) Synaptic vesicles. Answer: C 11) Calcium ions. Answer: A 2 12) Postsynaptic membrane. Answer: B 13) Synaptic cleft. Answer: D MATCHING. Choose the item in column 2 that best matches each item in column 1. Match the following: 14) The neuron cannot respond to a second stimulus, no matter how strong. A) Absolute refractory period B) Action potential Answer: A 15) The interior of the cell becomes less negative due to an influx of sodium ions. Answer: C C) Depolarization D) Relative refractory period E) Repolarization 16) The specific period during which potassium ions diffuse out of the neuron due to a change in membrane permeability. Answer: E 17) Also called a nerve impulse transmitted by axons. Answer: B 18) An exceptionally strong stimulus can trigger a response. Answer: D Match the following: 19) Voltage- gated Na+ channels open. A) Hyperpolarization Answer: D B) Threshold stimulus 20) Na+ channels are inactivating, and voltage- gated K+ channels open. C) Repolarization Answer: C 21) Some K+ channels remain open, and Na+ channels rest. D) Depolarization Answer: A 22) Any stimulus at or above this level will result in action potential. Answer: B 3 Match the following: 23) Area where nerve impulse is generated. Answer: B 24) Receives stimuli. A) Receptive region B) Trigger zone C) Secretory region Answer: A 25) Plasma membrane exhibits voltage- gated Na+ and K+ channels. D) Conducting region E) Secretory zone Answer: D 26) Plasma membrane exhibits voltage- gated Ca2+ channels. Answer: C 27) Axon terminals release neurotransmitters. Answer: E 28) Plasma membrane exhibits chemically gated ion channels. Answer: A Match the following: 29) One incoming axon triggers responses in ever- increasing numbers farther and farther along the circuit. A) Converging circuit B) Reverberating circuit Answer: C 30) May be involved in complex, exacting types of mental processing. Answer: D C) Diverging circuit D) Parallel after- discharge circuit 31) Involved in control of rhythmic activities such as breathing. Answer: B 32) Involved in activating fibers of a skeletal muscle such as the biceps muscle. Answer: C 33) Different types of sensory input can have the same ultimate effect. Answer: A 4 TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false. 34) The all- or- none phenomenon as applied to nerve conduction states that the whole nerve cell must be stimulated for conduction to take place. Answer: True False 35) Reflexes are rapid, automatic responses to stimuli that will produce the same effect every time. Answer: True False 36) Cell bodies of sensory neurons may be located in ganglia lying outside the central nervous system. Answer: True False 37) During depolarization, the inside of the neuron's membrane becomes less negative. Answer: True False 38) The peripheral nervous system is divided into afferent and efferent divisions. Answer: True False 39) Strong stimuli cause the amplitude of action potentials generated to increase. Answer: True False 40) Enkephalins and endorphins are peptides that act like morphine. Answer: True False 41) In myelinated axons the voltage- regulated sodium channels are concentrated at the nodes of Ranvier. Answer: True False 42) A postsynaptic potential is a graded potential that is the result of a neurotransmitter released into the synapse between two neurons. Answer: True False 43) Unipolar neurons have axons structurally divided into peripheral and central processes. Answer: True False 44) A stimulus traveling toward a synapse appears to open calcium ion channels at the presynaptic end, which in turn promotes fusion of synaptic vesicles to the axonal membrane. Answer: True False 45) Axon diameter and degree of myelination determine nerve impulse conduction velocity. Answer: True False 46) The action potential is caused by permeability changes in the plasma membrane. Answer: True False 5 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 47) Nerve impulses are sent to slow the heart's rate of contraction. The nerve fibers sending these signals will most likely belong to which division of the nervous system? A) sensory (afferent) division B) somatic nervous system C) sympathetic division D) parasympathetic division Answer: D 48) Nerve impulses leading to the brain carry information about cool temperatures on the skin. The nerve fibers sending these signals will most likely belong to which division of the nervous system? A) sensory (afferent) division B) somatic nervous system C) sympathetic division D) parasympathetic division Answer: A 49) Nerve impulses leading to the skeletal muscle carry information to direct movement. The nerve fibers sending these signals will most likely belong to which division of the nervous system? A) sensory (afferent) division B) somatic nervous system C) sympathetic division D) parasympathetic division Answer: B 50) Cranial nerve II, the optic nerve sends nerve impulses to the brain carrying information about the things we see. These nerve fibers most likely belong to which division of the nervous system? A) sensory (afferent) division B) somatic nervous system C) sympathetic division D) parasympathetic division Answer: A 51) The concentration of ions in the chemical environment surrounding the neurons must be tightly regulated for neurons to function properly. Which of the following cells is most responsible for this? A) astrocytes B) satellite cells C) Schwann cells D) oligodendrocytes Answer: A 52) Some nerve fibers of the peripheral nervous system have the ability to regenerate after damage has occurred. Which of the following cells is most responsible for aiding in this regulation? A) Schwann cells B) astrocytes C) oligodendrocytes D) satellite cells Answer: A 53) It is important for newly developed neurons to form synapses with other neurons. Which cells are most responsible for guiding the formation of these particular junctions? A) microglial cells B) Schwann cells C) satellite cells D) astrocytes Answer: D 54) Meningitis can be caused by infection of the central nervous system by bacteria. Which cells would be most responsible for removing the infection? A) microglia B) satellite cells C) oligodendrocytes D) Schwann cells Answer: A 6 55) Like all cells, the neurons' internal organization dictates its function. Neurons have relatively many mitochondria, an extensive network of rough endoplasmic reticulum and many clusters of ribosomes. These cellular features indicate all of the following EXCEPT ________. A) neurons must meet a high demand for ATP B) neurons produce many proteins C) neurons have stable, relatively unchanging internal environments D) neurons have a relatively high consumption of oxygen Answer: C 56) An action potential is regarded as an example of a positive feedback. Which of the following examples below best illustrates the positive feedback aspect of an action potential? A) Potassium permeability is about 25 times greater than sodium ions. B) Voltage gated potassium ion channels open slowly and remain open long enough to cause hyperpolarization. C) A threshold stimulus will cause the opening of voltage gated sodium ion channels that will cause further depolarizing stimulus. This stimulus will open still more voltage gated sodium ion channels. D) The sodium potassium pump consistently moves ions as long as ATP is available, and regardless of membrane potential changes. Answer: C 57) The depolarization phase of an action potential is punctuated by the closing of inactivation gates in the voltage gated sodium ion channels. All of the following are consequences of this inactivation except one. Choose the statement below that is not a consequence of the closing of inactivating gates. A) This allows for the one way transmission of action potential down the axon. B) This allows for the efflux (diffusion out) of potassium ions, resulting in the repolarization of the cell. C) This limits the frequency of action potentials down the axon. D) This stops the depolarization of the axon membrane. Answer: B 58) During the relative refractory period of an action potential, a larger than normal stimulus is needed to cause another action potential. This is due to the fact that ________. A) the membrane is now impermeable to all ions B) the sodium potassium pump will stop working during relative refractory C) the voltage gated potassium ion channels remain open long enough to hyperpolarize the axon membrane D) the inactivation gates on voltage gated sodium ion channels are closed Answer: C 59) If a postsynaptic neuron is stimulated to threshold by spatial summation this implies that ________. A) the postsynaptic cell has many synapses with many presynaptic neurons B) the postsynaptic cell has many voltage gated ion channels C) the postsynaptic cell has a lower than normal threshold D) the postsynaptic cell is slow to repolarize Answer: A 60) If a postsynaptic cell is stimulated to threshold by temporal summation this implies that ________. A) the presynaptic neuron is sending frequent IPSP B) a presynaptic neuron is sending frequent EPSP C) the postsynaptic cell is sending frequent action potential D) the postsynaptic cell can be influenced by only one presynaptic cell Answer: B 7 61) When a neurotransmitter like acetylcholine is acting in an excitatory manner which of the following is likely a result of the acetylcholine acting on the postsynaptic cell? A) Chemically gated sodium channels will open. B) Chemically gated sodium channels will be closed. C) Chemically gated potassium channels will open. D) Chemically gated chloride channels will open. Answer: A 62) When a neurotransmitter like GABA is acting in an inhibitory manner which of the following is likely a result of the GABA acting on the postsynaptic cell? A) opening of chemically gated sodium channels B) hyperpolarization of the postsynaptic cell membrane C) depolarization of the postsynaptic cell membrane D) influx of positively charged ions into the postsynaptic cell Answer: B 63) The effect of acetylcholine can be stimulating or inhibiting. Which of the following gives the best explanation for why this is so? A) Acetylcholine has a "dose effect." Larger doses are stimulating while small doses inhibit. B) Postsynaptic cells have a dynamic and changing metabolism and respond differently at different times. C) Acetylcholine has many different forms. D) Different postsynaptic cells will have different receptors. Answer: D 64) Which of the following is NOT a function of dendrites? A) produce short- distance signals called graded potentials B) generate nerve impulses and transmit them away from the cell body C) provide enormous surface area for receiving signals from other neurons D) convey incoming messages toward the cell body Answer: B 65) Which of the choices below describes the ANS? A) motor fibers that conduct nerve impulses from the CNS to skeletal muscles B) sensory neurons that convey information from somatic receptors in the head, body wall, and limbs and from receptors from the special senses of vision, hearing, taste, and smell to the CNS C) sensory and motor neurons that supply the digestive tract D) motor fibers that conduct nerve impulses from the CNS to smooth muscle, cardiac muscle, and glands Answer: D 66) These cells in the CNS have cilia that move in order to circulate cerebrospinal fluid. A) ependymal cells B) astrocytes C) Schwann cells D) oligodendrocytes Answer: A 67) What does the central nervous system use to determine the strength of a stimulus? A) type of stimulus receptor B) frequency of action potentials C) origin of the stimulus D) size of action potentials Answer: B 8 68) Bipolar neurons are commonly ________. A) motor neurons C) called neuroglial cells B) found in ganglia D) found in the retina of the eye Answer: D 69) Which of the following is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle? A) gamma aminobutyric acid B) cholinesterase C) norepinephrine D) acetylcholine Answer: D 70) Which of the following describes the nervous system integrative function? A) analyzes sensory information, stores information, makes decisions B) responds to stimuli by gland secretion or muscle contraction C) senses changes in the environment Answer: A 71) The period after an initial stimulus when a neuron is not sensitive to another stimulus is the ________. A) absolute refractory period B) resting period C) depolarization D) repolarization Answer: A 72) Which of the following is NOT a characteristic of neurons? A) They conduct impulses. C) They have an exceptionally high metabolic rate. B) They have extreme longevity. D) They are mitotic. Answer: D 73) Which ion channel opens in response to a change in membrane potential and participates in the generation and conduction of action potentials? A) ligand- gated channel B) leakage channel C) voltage- gated channel D) mechanically- gated channel Answer: C 74) Loss of function in the enzyme acetylcholine esterase would result in which of the following? A) inability to release acetylcholine B) inability to destroy and remove acetylcholine from the synaptic cleft C) amplify or enhance the effect of ACh D) stimulation of the production of acetylcholine Answer: B 75) Which of the following is NOT a function of the autonomic nervous system? A) innervation of skeletal muscle B) innervation of glands C) innervation of smooth muscle of the digestive tract D) innervation of cardiac muscle Answer: A 76) Collections of nerve cell bodies outside the central nervous system are called ________. A) nuclei B) ganglia C) nerves Answer: B 9 D) tracts 77) The term central nervous system refers to the ________. A) somatic nerves C) spinal nerves B) sensory (afferent) nerves D) brain and spinal cord Answer: D 78) A neuron that has as its primary function the job of connecting other neurons is called a(n) ________. A) interneuron B) glial cell C) efferent neuron D) afferent neuron Answer: A 79) Saltatory conduction is made possible by ________. A) large nerve fibers C) erratic transmission of nerve impulses B) the myelin sheath D) diphasic impulses Answer: B 80) Which of the following is NOT a chemical class of neurotransmitters? A) nucleic acid B) ATP and other purines C) biogenic amine D) amino acid Answer: A 81) Which of the following is false or incorrect? A) An excitatory postsynaptic potential occurs if the excitatory effect is greater than the inhibitory effect but less than threshold. B) An inhibitory postsynaptic potential occurs if the inhibitory effect is greater than the excitatory, causing hyperpolarization of the membrane. C) A nerve impulse occurs if the excitatory and inhibitory effects are equal. Answer: C 82) Select the correct statement regarding chemical synapses. A) Cells with gap junctions use chemical synapses. B) The release of neurotransmitter molecules gives cells the property of being electrically coupled. C) The synaptic cleft uses the action potential to transmit a chemical signal to the postsynaptic cell. D) Neurotransmitter receptors are located on the axons terminals of cells. Answer: C 83) Which of the following correctly describes a graded potential? A) It has a depolarization, repolarization, and hyperpolarization phase. B) It can have amplitudes of various sizes. C) It travels long distances. D) It is initiated by voltage changes in the membrane. Answer: B 84) Schwann cells are functionally similar to ________. A) oligodendrocytes B) ependymal cells C) astrocytes D) microglia Answer: A 85) Immediately after an action potential has peaked, which of the following channels will open? A) voltage- gated calcium channels B) voltage- gated sodium channels C) voltage- gated potassium channels D) chemically- gated chloride channels Answer: C 10 86) An inhibitory postsynaptic potential (IPSP) is associated with ________. A) opening of voltage- regulated channels B) lowering the threshold for an action potential to occur C) hyperpolarization D) a change in sodium ion permeability Answer: C 87) Which of the following will occur when an excitatory postsynaptic potential (EPSP) is being generated on the dendritic membrane? A) Sodium gates will open first, then close as potassium gates open. B) Specific sodium gates will open. C) A single type of channel will open, permitting simultaneous flow of sodium and potassium. D) Specific potassium gates will open. Answer: C 88) When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________. A) generator potential B) excitatory potential C) action potential D) postsynaptic potential Answer: A 89) Which of the following is NOT true of graded potentials? A) They can be called postsynaptic potentials. B) They increase amplitude as they move away from the stimulus point. C) They are short- lived. D) They can form on receptor endings. Answer: B 90) Which of the following is true about the movement of ions across excitable living membranes? A) Ions always move actively across membranes through leakage channels. B) Sodium gates in the membrane can open in response to electrical potential changes. C) Ions always move passively across membranes. D) Ions always move from an area of higher concentration to an area of lower concentration. Answer: B 91) A second nerve impulse cannot be generated until ________. A) the Na ions have been pumped back into the cell B) proteins have been resynthesized C) the membrane potential has been reestablished D) all sodium gates are closed Answer: C 92) The interior surface of a neuron's plasma membrane at resting membrane potential will have a ________. A) positive charge and contains less sodium than outside of the cell B) negative charge and contains more sodium than outside of the cell C) negative charge and contains less sodium than outside of the cell D) positive charge and contains more sodium than outside of the cell Answer: C 11 93) If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon, ________. A) the impulse would move to the axon terminal only, and the muscle contraction would occur B) the impulse would spread bidirectionally C) muscle contraction would occur D) the impulse would move to the axon terminal only Answer: B 94) Which of the following neurotransmitters is the principal inhibitory neurotransmitter of the spinal cord? A) serotonin B) glycine C) endorphin D) acetylcholine Answer: B 95) Which of the following describes the excitatory postsynaptic potential? A) short distance depolarization B) opens K + or Cl- channels C) moves membrane potential away from threshold D) short distance hyperpolarization Answer: A SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 96) The part of the nervous system that conducts impulses from the CNS to the skeletal muscles is the ________ nervous system. Answer: somatic 97) Neuroglia found in the CNS that change the permeability of capillaries in the brain by binding to and surrounding these blood vessels are called ________. Answer: astrocytes 98) Which group of neurotransmitters play a role in emotional behavior and help regulate the biological clock? Answer: biogenic amine neurotransmitters 99) What mechanism is responsible for axonal transport? Answer: ATP- dependent "motor" proteins such as kinesin and dynein myosin are responsible. They propel cellular components along microtubules. 100) The synapse more common in embryonic nervous tissue than in adults is the ________. Answer: electrical synapse 101) When information is delivered within the CNS simultaneously by different parts of the neural pathway, the process is called ________ processing. Answer: parallel 102) When one or more presynaptic neurons fire in rapid order it produces a much greater depolarization of the postsynaptic membrane than would result from a single EPSP; this event is called ________ summation. Answer: temporal 12 103) What is the role of microglial cells and why are they so important in the CNS? Answer: In the presence of invading microbes, microglial cells become macrophages to phagocytize the microbes and neuronal debris. This protective role is important because cells of the immune system are denied access to the CNS. 104) Define synaptic delay. Answer: Synaptic delay reflects the time required for neurotransmitter release, diffusion across the synaptic cleft, and binding to receptors. 105) What is the difference between a direct acting neurotransmitter and an indirect acting neurotransmitter? Answer: Direct acting neurotransmitters bind to and open ion channels. Indirect acting neurotransmitters act through intracellular second- messenger molecules. 106) What function is served by the increased axon diameter at the nodes of Ranvier? Answer: Increased diameter results in less resistance to lengthwise intra- axonal flow. This results in increased speed of impulse propagation. 107) Imagine a neuron that has several hundred axonal knobs impinging on it. The majority of these axonal knobs are shown to be "firing." However, the neuron in question does not transmit an impulse. Give a valid explanation of why this could occur. Answer: Both excitatory and inhibitory potentials impinge on neurons. In this case, inhibitory postsynaptic potentials (IPSPs) outnumber EPSPs, and due to the IPSP neurotransmitter released and its action, the postsynaptic neuron is inhibited from "firing" (hyperpolarized). 108) At the biochemical level, what is the explanation of the hyperpolarization phase at the conclusion of the action potential? Answer: The voltage gated K+ channels are slow to open as well as to close. These channels will remain open long enough to hyperpolarize the cell. The K+ ions decrease the positive ion concentration momentarily below the normal - 70mV and thus hyperpolarize the cell. This assists in preventing the AP from reversing direction. 109) What are the basic divisions of the peripheral nervous system? Answer: Sensory and motor divisions. Sensory has two divisions: the somatic and visceral. Motor has two divisions: the somatic and autonomic. The autonomic has two divisions: the sympathetic and parasympathetic. 110) Because all action potentials are alike, how does the brain separate situations that require immediate attention from ordinary "positional" reports? Answer: The importance of a stimulus is derived from the number of stimuli received from the same source. The frequency of impulse transmission indicates the stimulus intensity and the brain responds appropriately. ESSAY. Write your answer in the space provided or on a separate sheet of paper. 111) Multiple sclerosis (MS) is a disease in which the myelin sheaths are destroyed. What process does this interfere with and what would be the consequence? Answer: Demyelination interferes with saltatory conduction, which would result in a slowing down and even permanent cessation of nerve impulse propagation. 13 112) A patient is admitted to the hospital with exacerbation of multiple sclerosis (MS). She asks the nurse, "Why did this have to happen to me again? I was doing so well." Explain why some forms of MS are characterized by periods of remission and exacerbation. Answer: Even though someone is diagnosed with MS, the axons are not damaged. Growing numbers of sodium channels appear spontaneously in the demyelinated fibers so that conduction resumes, even if slower. This may account for the cycles of relapse and remission in different patients. 113) A heroin addict was brought into the emergency room. The addict's friend asks the emergency room physician why heroin and morphine are such addictive drugs. How does the physician respond? Answer: The physician would respond that heroin, morphine, and other opiates cause the body to have the same responses as when endorphins are released. Endorphins are neurotransmitters that inhibit pain. 114) What symptoms would a nurse focus on in his or her care of a patient with multiple sclerosis? Answer: Visual disturbances, paralysis, and weakness 115) Sally, a 5- year- old child, was bitten on the hand by a bat that was later diagnosed with rabies. She was immediately treated after the bite but had to go through a series of more involved treatments after the rabies diagnosis in the bat that bit her. How does the rabies virus get to the brain from a simple hand wound? Answer: The rabies virus uses retrograde axonal transport to reach the neuron cell bodies as it makes its way to the brain cells. 14