1. Which statement about the plasticity of synapses in the mammalian CNS is false? A. calcium ions play a central role in at least some forms of synaptic plasticity B. the efficacy of synapses can be adjusted by modulating the amount of neurotransmitter that is released C. a variety of molecular mechanisms are involved in the different forms of synaptic plasticity D. the hallmark of both short-term and long-term synaptic plasticity is that they always increase in the strength of synaptic connections E. changes in synaptic efficacy can occur over time scales ranging from milliseconds to years 2. after firing a short burst of action potentials in an axon, researchers observe a larger EPSP in the post synaptic cell, and this effect seems to last a few tens to milliseconds. This is most likely due to the presynaptic terminal having A. reduced sodium B. lowered calcium C. extra calcium D. extra magnesium E. extra sodium 3. Which mechanism would be a plausible explanation for synaptic depression? A. inhibition of postsynaptic calcium channels B. activation of presynaptic potassium channels C. depletion of docked synaptic vesicles in the presynaptic terminal D. enhancement of presynaptic sodium currents E. Faster replenishment of vesicles to the reserve pool
Added by Kelly W.
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Step 1: The false statement about the plasticity of synapses in the mammalian CNS is that the hallmark of both short-term and long-term synaptic plasticity is that they always increase in the strength of synaptic connections. Show more…
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1.) ____ of the neuron experience(s) resting membrane potential because of the presence of ____ that are the dominant contributors to the process. A. Dendrites, pumps B. Soma, ligand-gated channels C. Axon, voltage-gated channels D. Terminals, receptors E. All regions, leak channels 2.) Glia provide supportive nervous system functions such that: A. Ependymal cells provide immune responses B. Microglia circulate CSF C. Oligodendrocytes regulate substances entering the brain from capillaries D. Schwann cells myelinated axons in the spinal cord E. Astrocytes perform signal cessation by absorbing neurotransmitter 3.) Resting membrane potential: A. Sits close to potassium equilibrium potential because potassium voltage-gated channels are more numerous than sodium non-gated channels B. Utilizes high levels of energy because it is mainly established by the Na/K ATPase C. Is a result of high intracellular sodium and large anionic proteins D. Produces an electrochemical gradient that favors sodium efflux through voltage-gated channels because of its large driving force E. No option is correct 4.) Flow of potassium across a typical neuron embrace leads to ____ events that move the neuron ____ threshold, while ____ has the opposite response. A. EPSP... toward... sodium B. IPSP... away from... calcium C. Negative feedback... directly to... protein D. Positive feedback... closer to... chloride E. No option is correct 5.) Positive feedback occurs when a factor ____. An example happens during ____, which involves the ion ____ and an off-switch called ____. A. Continually decreases... resting repolarization phase... potassium... channel inactivation B. Reverses itself... action potential depolarization phase... potassium... channel closing C. Continually increases... action potential depolarization phase... sodium... channel inactivation D. Moves toward homeostasis... synaptic transmission depolarization phase... calcium... channel activation E. No option is correct 6.) Match the letter with the statement, some may require more than one. A. Rest B. Depolarization C. Repolarization D. Hyperpolarization ____ 1. Mediated by voltage-gated channels ____ 2. Requires sodium influx ____ 3. Phase of action potential ____ 4. Occurs when potassium channels close ____ 5. Involves a positive feedback loop
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Which of the below answers is NOT correct concerning a preganglionic neuron? Select one: a. Its cell body is in the brain or spinal cord. b. It forms a gap junction with the postganglionic neuron. c. It forms the first part of an autonomic motor pathway. d. Its axon exits the CNS with a cranial or spinal nerve. 2. The formation of a blood clot is known as which of the following? Select one: a. Leukocytosis b. Erythropoiesis c. Hemostasis d. Coagulation 3. A person with A+ blood group has the following antigens on his red blood cells. Select one: a. Has A antigen but lacks B antigen and Rh antigen. b. Has A antigen but lacks Rh antigen. c. Has A antigen and Rh antigen. d. Has A antigen, B antigen, and Rh antigen. 4. Which one of the following is made up primarily of fibers producing epinephrine? Select one: a. Preganglionic neurons of the sympathetic division b. Postganglionic neurons of the sympathetic division c. Postganglionic neurons of the parasympathetic division d. All motor fibers of the somatic motor system 5. Motor neurons of the Enteric nervous system monitor: Select one: a. The secretion of gastric cells b. The blood pressure c. The heart rate d. The contraction of the abdominal skeletal muscles 6. Which of the following is associated with the "flight-or-fight" reaction? Select one: a. Increased gastric motility b. Reduced urinary output c. Glycogen synthesis d. Pupillary constriction 7. Which of these actions is not a flight-or-flight response? Select one: a. Constricting blood vessels b. Dilatation of the pupil of the eyes c. Stimulation of lacrimation d. Increasing blood glucose level 8. The gap between two adjacent myelin segments along an axon is called the: Select one: a. Axonal cleft b. Node of Ranvier c. Leakage d. Synaptic cleft
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Neurotransmitters are released from presynaptic axon terminals into the synaptic cleft by which mechanism? A) osmosis B) active transport C) diffusion D) endocytosis E) exocytosis Which of the following statements about the loop of Henle is true? A) The walls of the descending loop are relatively impermeable to water B) The walls of the descending loop are relatively permeable to sodium C) The walls of the ascending loop are relatively permeable to water D) The walls of the ascending loop are relatively permeable to sodium Which of the following statements is the BEST explanation for the presence of four-chambered hearts in both birds and mammals? A) They shared a common ancestor that had a four-chambered heart. B) They are the only vertebrates with double circulation, which requires four heart chambers. C) They are both endotherms and the evolution of efficient circulatory systems supported the high metabolic rate of endotherms. D) None of these can explain the presence of a four-chambered heart. Neurotransmitters affect postsynaptic cells by A) causing molecular changes in the cells related to ion concentrations B) affecting ion-channel proteins. C) altering the ion permeability of the cells. D) all of the above
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