Bio 2 – Exam 1 (Ch. 43) Questions – Flashcards
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What are examples of cells that support neurons both structurally and functionally? A. dendrites and nodes of Ranvier B. neuroglia and nodes of Ranvier C. Schwann cells and dendrites D. dendrites, nodes of Ranvier, and neuroglia E. Schwann cells, oligodendrocytes, and other neuroglia
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E. Schwann cells, oligodendrocytes, and other neuroglia
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You dissect the brain of a mutant mouse and find that parts of the "white matter" look gray. What is a likely cause? A. defects in myelination B. peripheral nerve damage C. oversized dendrites D. excess myelination E. excess neuronal proliferation
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A. defects in myelination
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You are studying a gene which, when mutant, causes oligodendrocytes to enwrap shorter sections of axon, so that nodes of Ranvier are more closely spaced. What is the likely effect on nerve impulses? A. They will travel faster. B. They will travel slower. C. They will increase in amplitude. D. They will decrease in amplitude. E. They will travel laterally across connected axons.
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B. They will travel slower.
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Rapid inward diffusion of Na+ produces a dramatic change in membrane potential. What is this event called? A. hyperpolarization B. excitatory postsynaptic potential C. saltatory conduction D. monosynaptic reflex E. depolarization
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E. depolarization
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Nerve impulses are electrical signals produced by which structure? A. lipid sheath of Schwann cell B. plasma membrane of neuron C. synapse D. neuromuscular junction
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B. plasma membrane of neuron
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The membrane of a resting neuron is most permeable to which of the following ions? A. ClB. Ca2+ C. Na+ D. K+ E. H+
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D. K+
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At myelinated areas of the axon (i.e. between nodes of Ranvier), which of the following statements is true? A. There is an increased number of voltage-gated sodium channels. B. There is increased resistance across the membrane. C. There is increased capacitance across the membrane. D. There is increased transport of potassium across the membrane.
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B. There is increased resistance across the membrane.
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Which ion channel is primarily responsible for the action potential? A. the voltage-gated sodium channel B. the voltage-gated potassium channel C. the ligand-gated sodium channel D. the ligand-gated potassium channel E. the non-gated sodium channel
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A. the voltage-gated sodium channel
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What diffuses across the narrow synaptic cleft between the presynaptic axon and the postsynaptic cell to transmit a nerve impulse? A. neurotransmitter B. electrical impulse C. Na+ ion D. vesicle E. action potential
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A. neurotransmitter
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Which neurotransmitter is released from a motor neuron at the neuromuscular junction? A. acetylcholine B. GABA C. ephinephrine D. dopamine E. serotonin
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A. acetylcholine
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Place the following events that occur at the vertebrate neuromuscular junction in the correct order. I-Depolarization of the muscle fiber membrane. II-Generation of an action potential in the neuron. III-Stimulation of Ca2+ entry into the neuron. IV-Release of acetylcholine into the synapse. A. I, II, III, IV B. III, II, IV, I C. I, III, IV, II D. IV, II,III, I E. II, III, IV, I
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E. II, III, IV, I
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Which of the following are example of biogenic amines? A. epinephrine and endorphins B. GABA and serotonin C. epinephrine, dopamine, and GABA D. epinephrine, dopamine, and serotonin E. epinephrine, norepinephrine, dopamine, and serotonin
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E. epinephrine, norepinephrine, dopamine, and serotonin
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The hippocampus, amygdala, and hypothalamus are the major components of the ______ system. A. sympathetic B. reflex C. parasympathetic D. limbic E. autonomic
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D. limbic
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The spinal cord is enclosed by the vertebral column and layers of protective membranes. What are these membranes called? A. neural net B. white matter C. dorsal root D. meninges E. viscera
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D. meninges
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Damage to the substantia nigra, a specific region of the basal ganglia, can produce the resting muscle tremors characteristic of what disease? A. epilepsy B. Parkinson disease C. seizures D. Alzheimer disease E. insomnia
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B. Parkinson disease
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A region of the brain receives both sensory information from ascending nerve tracts and motor commands from the cortex and cerebellum. This region plays an important role in motor control. Which region is it? A. basal ganglia B. pituitary gland C. parietal lobe D. thalamus E. medulla oblongata
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A. basal ganglia
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Which area of the cerebral cortex is important for the formulation of thoughts into speech? A. Broca's area B. the pons C. the medulla oblongata D. Wernicke's area E. the cerebellum
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D. Wernicke's area
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In early vertebrates, which component of the brain was devoted largely to coordinating motor reflexes? A. thalamus B. forebrain C. midbrain D. hindbrain E. medulla oblongata
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D. hindbrain
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Where did information processing become increasingly centered in terrestrial vertebrates? A. thalamus B. forebrain C. midbrain D. hindbrain E. medulla oblongata
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B. forebrain
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Which region of the CNS listed below is NOT correctly paired with its function? A. Broca's and Wernicke's areas—language and speech B. Hypothalamus—regulates body temperature, appetite, and sleep C. Cerebellum—relay station for ascending and descending tracts D. Corpus callosum—connects the two brain hemispheres E. Hippocampus—memory
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C. Cerebellum—relay station for ascending and descending tracts
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Which major regions compose the contemporary vertebrate brain? A. rhombencephalon and prosencephalon only B. mesencephalon and rhombencephalon only C. prosencephalon and metencephalon only D. metencephalon, rhombencephalon, and prosencephalon E. rhombencephalon, mesencephalon, and prosencephalon
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E. rhombencephalon, mesencephalon, and prosencephalon
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Which of the following structures is NOT a component of the hindbrain? A. pons B. medulla oblongata C. ascending tracts D. cerebellum
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C. ascending tracts
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What is the primary function of the hindbrain in vertebrates? A. temperature control B. integration of sensory data C. memory storage D. control of the heartbeat E. coordination of motor reflexes
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E. coordination of motor reflexes
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Where do correlation, association, and learning occur in the brain? A. cerebellum B. corpus callosum C. medulla D. cerebrum E. pons
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D. cerebrum
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What is the site of primary sensory integration in the brain? A. medulla oblongata B. cerebrum C. cerebellum D. thalamus E. corpus callosum
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D. thalamus
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Which of the following is NOT a feature of the limbic system? A. contains hippocampus and amygdala B. resides deep within the cerebrum C. responsible for emotional responses D. important in the formation and recall of memories E. part of the hypothalamus
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E. part of the hypothalamus
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What additional factor is required to mediate the parasympathetic effects of acetylcholine? A. G-protein coupled receptor B. GABA C. AMPAR D. habituation E. synaptic integration
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A. G-protein coupled receptor
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Which of the following is not part of the peripheral nervous system? A. sympathetic division of the autonomic nervous system B. spinal cord C. parasympathetic division of the autonomic nervous system D. somatic nervous system E. sensory pathways
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B. spinal cord
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Dr. Robinson tapped on a patient's knee with the little hammer, but failed to see the usual kick of the patellar reflex. Since this reflex only involves a few neurons, what part of the nervous system might the doctor became concerned about? A. parasympathetic nervous system B. central nervous system C. sympathetic nervous system D. peripheral nervous system
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D. peripheral nervous system
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Subsequent to motor neuron degeneration in Charcot-Marie-Tooth disease, muscles begin to weaken and degenerate as well. What is the likely cause? A. Muscles will atrophy if they don't receive regular stimulation from motor neurons. B. Muscles require healthy Schwann cells for myelination as well. C. Muscles contain large numbers of mitochondria. D. Toxins leak out from the dying motor neurons onto the muscles.
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A. Muscles will atrophy if they don't receive regular stimulation from motor neurons.
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What part of the neuron is responsible for most of the "house-keeping" tasks of the cell, including protein synthesis? A. myelin B. axon C. dendrite D. soma E. synapse
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D. soma
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How does the resting potential of a typical neuron compare to that of a 1.5V AA alkaline battery? A. A typical neuron has a resting potential of -70mV, or about 5% the voltage of the battery. B. A typical neuron has a resting potential of -70V, or about 50x the voltage of the battery. C. A typical neuron has a resting potential of +70mV, or about 5% the voltage of the battery. D. A typical neuron has a resting potential of +70V, or about 50x the voltage of the battery.
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A. A typical neuron has a resting potential of -70mV, or about 5% the voltage of the battery.
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To process information, postsynaptic neurons often add up simultaneous signals from several presynaptic neurons. Which structure and process allow them to do so? A. axons; temporal summation B. axons; spatial summation C. dendrites; temporal summation D. dendrites; spatial summation
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D. dendrites; spatial summation
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A neuron that engages in spatial summation acquires a mutation that causes dendrite overgrowth and promiscuous synapsing. What is the likely outcome? A. abnormally low frequency of action potentials B. summation will not occur C. abnormally high frequency of action potentials D. action potentials with stronger depolarization
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C. abnormally high frequency of action potentials
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True or false: neurons are the only electrically-active cells.
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FALSE Muscles are also formed from electrically-active cells.
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What important resource do Schwann cells and oligodendrocytes provide to neurons? A. oxygen B. nutrients C. physical strength from microtubules D. Ca2+ currents E. insulating layers of membrane
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E. insulating layers of membrane
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A patient suffers from a disease that slows fatty acid synthesis. What is a likely impact of this disease on nervous system function? A. improved functioning due to a healthier weight B. insufficient myelination and slow axon conduction rate C. improved functioning due to better blood flow D. weaker action potentials with smaller depolarization
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B. insufficient myelination and slow axon conduction rate
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True or false: When a neuron is not firing, the sodium-potassium pump is inactive.
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FALSE Even when a neuron is not firing, the pump is maintaining the resting membrane potential by transporting ions that are constantly leaking out through the leak channels.
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"Synapses are connections between the axon of one neuron and the dendrite of another neuron, where neurotransmitters transmit a chemical signal." How would you modify this statement to make it more complete? (Check all that apply.) 1 The statement needs no modification. 2 Synapses can also form between an axon and a cell soma. 3 Neuromuscular synapses form between the axon of a neuron and a muscle. 4 Synapses often form among the parts of a single cell. 5 Synapses can be electrical as well as chemical.
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2, 3, and 5
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Choose the two primary factors that contribute to the resting membrane potential of a neuron. 1 K+ leak channels make the cell membrane more permeable to K+ 2 The sodium-potassium pump exports 3 K+ from the cell for every 2 Na+ it imports 3 Na+ leak channels make the cell membrane more permeable to Na+ 4 K+ leak channels cause a higher concentration of K+ outside the cell. 5 The sodium-potassium pump exports 3 Na+ from the cell for every 2 K+ it imports
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1 and 5
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Three-quarters of the substantial amount of energy consumed by the brain is used to run a single molecular machine that maintains the resting potential of neurons. What is this machine called? A. K+ leak channel B. sodium-potassium pump C. acetylcholine receptor D. voltage-gated sodium channel E. voltage-gated calcium channel
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B. sodium-potassium pump
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Since there is a larger concentration of potassium ions inside a neuron, why is the inside of the neuron negative (-70mV) relative to the outside? A. Potassium ions carry a negative charge. B. Negatively-charged proteins inside the cell counteract the charge of the potassium ions. C. The negative sign is just a historical convention. D. The high concentration of sodium ions outside the cell makes the inside negative by comparison.
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B. Negatively-charged proteins inside the cell counteract the charge of the potassium ions.
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Sodium ions are single atoms. Why can't they simply diffuse through the cell membrane's lipid bilayer? A. Since they are charged, ions can't cross the hydrophobic center of the membrane without a channel or pump. B. Sodium ions are covalently attached in groups of three, which are too large to diffuse easily. C. Ions do traverse the membrane easily, but the sodium-potassium pump moves them back across. D. Chelator proteins capture any ions that start to cross the bilayer.
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A. Since they are charged, ions can't cross the hydrophobic center of the membrane without a channel or pump.
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The outside of a neuron is positively charged at resting potential. Why do K+ ions leave the cell when K+ channels open during an action potential? A. The diffusion gradient is the only factor that affects ion movement. B. K+ ions are actively pumped out by the sodium-potassium pump acting in reverse. C. Voltage-gated K+ channels open when membrane potential reaches +50 mV during the depolarization phase. The diffusion gradient and electrical force cooperate to drive K+ ions out of the cell. D. Negatively charged proteins leave the cell at the onset of the action potential.
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C. Voltage-gated K+ channels open when membrane potential reaches +50 mV during the depolarization phase. The diffusion gradient and electrical force cooperate to drive K+ ions out of the cell.
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The outside of a neuron is positively charged at resting potential. Why don't negative ions exit from the cell to normalize charge across the membrane? A. The positive charge outside the cell repels negative ions. B. There are no negative ions inside the cell. C. All of the chloride ions are already outside the cell. D. The negative charge inside the cell is carried by large proteins that cannot diffuse through the membrane.
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D. The negative charge inside the cell is carried by large proteins that cannot diffuse through the membrane.
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What does the Nernst equation allow us to do? A. Predict the function of a specific type of neuron. B. Calculate the equilibrium potential for an ion. C. Use a computer program to model axonal transmission. D. Calculate the magnitude of depolarization during an action potential.
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B. Calculate the equilibrium potential for an ion.
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When an action potential begins and sodium channels open, why does sodium rush into the cell? (Check all that apply.) 1 The inside of the cell is negatively charged. 2 The inside of the cell is positively charged. 3 Chloride ions are waiting to bind to the sodium inside the cell. 4 The diffusion gradient drives sodium into the cell. 5 Channels use energy to move ions across the membrane whenever they are open.
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1 and 4
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What is the basis of the typical -70mV resting potential in neurons? Rank the factors in order from most important to least important. 1 Ca+2 equilibrium potential 2 K+ equilibrium potential 3 Na+equilibrium potential
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2,3,1
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Your roommate takes up smoking, and you hate it. Use what you know about nicotine to convince her to quit. (Check all statements that are true.) 1 Nicotine binds to a receptor in the brain that normally receives acetylcholine. 2 Nicotine evolved to protect the tobacco plant by killing grazing cattle. 3 The brain adapts to smoking by changing the levels of this receptor. Over time, more drug is required to get the same effect. 4 Nicotine is not addictive, but is still very dangerous. 5 Nicotine is identical to an endogenous ligand in the human body. 6 Nicotine evolved to protect the tobacco plant by killing insects.
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1,3,6
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A patient of yours is injured in a car accident. The surgeon reports that while there is damage to the dorsal roots, the spinal cord and nerves otherwise appear intact. What functions would you expect to be affected in the patient? A. The patient may lose somatic function, but should retain autonomic function. B. The patient may lose motor function, but should retain sensory perception. C. The patient may lose some sensory perception, but should retain motor function. However, lack of proprioceptive input may make muscle control difficult. D. The patient may lose parasympathetic function, but should retain sympathetic function. They should avoid stressful situations.
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C. The patient may lose some sensory perception, but should retain motor function. However, lack of proprioceptive input may make muscle control difficult.
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Botulinum toxin, or "botox", has become popular for cosmetic surgery. The toxin prevents neurosecretory vesicles from docking at the plasma membrane and releasing neurotransmitter. How would this toxin affect the neuromuscular junction? A. Since ACh is not released, the muscles stay in a state of repeated contraction. B. Since ACh is not released, the muscles are not activated to contract and remain relaxed. C. Buildup of ACh causes promiscuous activation of all nearby sensory neurons. D. Buildup of ACh leaks back into the brain, creating a calming effect.
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B. Since ACh is not released, the muscles are not activated to contract and remain relaxed.
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You accidentally consume botulinum toxin by eating a contaminated can of sausages. What do you predict will be the most harmful physiological effect? A. slowed action potential conduction B. respiratory failure due to spastic paralysis (constant muscle contraction) C. respiratory failure due to flaccid paralysis (relaxed muscles) D. pupil dilation
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C. respiratory failure due to flaccid paralysis (relaxed muscles)
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Another toxin that also blocks neurotransmitter release is tetanus toxin; however, it primarily affects inhibitory interneurons of the spinal cord that negatively regulate motor neurons. Which would be symptoms of tetanus toxin poisoning? A. flaccid paralysis B. spastic paralysis C. slowed action potential conduction D. pupil dilation
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B. spastic paralysis
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K+ channels in the heart do not have binding sites for ACh, yet parasympathetic release of ACh causes outward flux of K+ from heart cells. How does this occur? A. ACh triggers release of epinephrine from the adrenal glands, which in turn causes K+ flux out of heart cells. B. ACh binds to a G-protein coupled receptor on heart cells, and the G protein alpha subunit binds to a separate K+ channel and causes it to open. C. Parasympathetic neurons activate sympathetic neurons, which directly cause K+ flux from heart cells. D. ACh binds and activates a K+ pump on heart cells.
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B. ACh binds to a G-protein coupled receptor on heart cells, and the G protein alpha subunit binds to a separate K+ channel and causes it to open.
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What would happen if the G-protein coupled receptor in heart cells that binds to ACh had a mutation that caused it to bind more tightly to the G-protein alpha subunit? A. G-protein activation and K+ channel opening would happen more quickly. Heart rate may remain abnormally low, impairing response to stress. B. This would lead to K+ flow out of heart cells, causing increased hyperpolarization. C. G-protein activation and K+ channel opening would be slowed. Heart rate may remain abnormally high, especially following stress. D. This would lead to K+ flow into heart cells, causing increased depolarization.
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C. G-protein activation and K+ channel opening would be slowed. Heart rate may remain abnormally high, especially following stress.
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How do somatic neurons and autonomic neurons differ? (Check all that apply.) 1 Somatic neurons innervate the body surface, while autonomic neurons innervate internal structures. 2 Somatic neurons control skeletal muscle, while autonomic neurons control smooth and cardiac muscle. 3 Somatic neurons control exocrine glands, while autonomic neurons do not. 4 Somatic neurons control their effectors directly, while autonomic neurons use a series of neurons. 5 Somatic neurons are always excitatory, while autonomic neurons may be either excitatory or inhibitory.
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2,4,5
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Why are mammalian reflexes so fast? (Check all that apply.) 1 They use neurons with extra-wide axons. 2 They complete the sensory input-to-motor output circuit in only 2-3 neurons. 3 They do not send signals to the brain and back. 4 They activate a large number of sensory neurons, which speeds things up after the motor neuron performs spatial summation. 5 There was a selective advantage to evolve rapid responses to certain types of stimuli.
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2,3,5
