Neurophysiology: Exam I

Name: ____________________________ Exam I (100 pts) Multiple-choice (3 pts each) 1) Which of the following is a true statement? A) Hippocrates stated that the heart was the center of emotion and consciousness. B) Galen’s view, the brain controls muscles by moving fluid through neurons, lasted 1500 years. C) Broca was a physician to gladiators who was a mute. D) All of the above. E) None of the above. 2) Which of the following is a true statement? A) Ben Franklin’s discoveries led to the idea that neurons use electric impulses to communicate. B) Staining developed by Golgi helped people finally see what neurons looked like. C) Cajal, unlike Golgi, thought that neurons had tiny gaps separating them. D) All of the above. E) None of the above. Match the following parts of a neuron to the best description. (Note: answers can be used more than once or not at all). A) Axon B) Synaptic cleft C) Cell body D) Dendrites E) Axon terminal 3) Where temporal summation occurs. 4) Has many voltage-gated Ca2+ channels 5) Neuronal projection with many chemically-gated channels 6) Is the final destination for dynein molecules. 7) Sometimes has glial cells wrapped around it. 8) Which of the following is a true statement? A) The brain has about as many glial cells as it does neurons. B) A single neuron can make connection with thousands of other neurons. C) Some neurons can have conduction speeds of 1000 meters per second. D) All of the above. E) None of the above. 9) Which of the following is a true statement? A) Microtubules are larger than are neurofilaments. B) Microtubules run in parallel down the length of the axon. C) Microtubules are used for trafficking material to different parts of the neuron. D) All of the above. E) None of the above. 10) Which of the following is a true statement? A) Small diameter axons conduct action potentials more slowly than so large diameter axons. B) Myelination speeds up conduction speeds by insulating the axon from Na+ leakage. C) Non-myelinated axons don’t have Nodes of Ranvier. D) All of the above. E) None of the above. 11) In order for a presynaptic neuron to send a bigger signal to a postsynaptic neuron it must… A) send larger action potentials. B) increase the frequency with which it is sending action potentials. C) All of the above. D) None of the above. Use the following figure of an action potential to answer the questions 12-16. (Note: letters can be used more than once or not at all). C D A B E 12) The neuron cannot fire an action potential because it’s in a refractory period. 13) The membrane potential is about -65mV. 14) The voltage-gated Na+ channels activation gates are closed but the inactivation gates are open. 15) The neuron is depolarizing without using voltage-gated channels. 16) Both gates of the voltage-gated Na+ channels are open. 17) Which of the following is a true statement? A) Ion channels have slower effects than do metabotropic receptors. B) Cations passing through an ion channel will always cause an EPSP. C) Voltage-gated channels open when glutamate binds to them. D) The effects of G-protein coupled receptors last longer than ion channels. E) None of the above. 18) A deficiency in the amino acid tryptophan would most likely cause problems with… A) Acetylcholine neurons. B) GABA neurons. C) Norepinephrine neurons. D) Serotonin neurons. E) Dopamine neurons. 19) True or False? If a cell is at an ion’s equilibrium potential there is no net movement of that ion. A) True. B) False. Use the following figure to answer the following questions 20-23. X Y W Z 20) If neuron X is excitatory and fires multiple action potentials to bring neuron W to threshold… A) spatial summation is occurring. B) temporal summation is occurring. C) inhibition shunting is occurring. D) All of the above are true. E) None of the above is true. 21) Based only on the location of the synapses, which neuron would have the easiest time getting neuron W to fire an action potential? A) neuron X B) neuron Y 22) If Neuron W’s upper dendrite has a much smaller length constant than its lower dendrite, an action potential traveling down which neuron would have a more likely chance of getting neuron W to fire? A) neuron X B) neuron Z 23) For shunting inhibition to occur which neuron must release GABA? A) neuron X B) neuron Y C) neuron Z D) neurons X, Y, and Z E) None of the neurons. 24) Which of the following is true about a nicotinic receptor? A) It will open when nicotine binds to it. B) It will open when curare binds to it. C) It won’t open if acetylcholine binds to it. D) It will open if glutamate binds to it. E) It will open if muscarine binds to it. 25) The neuron to the right is what kind of neuron? A) Unipolar B) Bipolar C) Multipolar 26) Which of the following is true about an NMDA receptor? A) Glutamate is the only known chemical that can bind to the receptor. B) Both Na+ and Ca2+ can pass through an open NMDA channel. C) At the resting membrane potential, ions can pass through the channel if glutamate binds to it. D) All of the above are true. E) None of the above is true. Short answer questions 27) (6 pts) John was having one of his cholinergic (releases acetylcholine) neurons (X) signal a postsynaptic neuron (Y). But now he wants neuron Y to stop receiving the signals. Besides having neuron X stop sending action potentials down to the terminal, what other things must occur for the postsynaptic neuron to no longer receive a signal? Neuron X (cholinergic) Neuron Y 28) (4 pts) A pixie cell has the same amount of the ion P2+ inside and outside the cell. When a channel for P2+ opens, the ion rushes out of the cell. How is this possible? 29) (6 pts) For the cell in the figure to the right, draw both the chemical and electrical forces acting on the ion X2-. If a channel for the ion is opened, in which direction with X2- flow? (into the cell, out of the cell) [X2-]o = 11mM [X2-]i = 0.11mM -61mV 30) (6 pts) Using the typical concentrations of Na+ inside and outside of a cell, if an AMPA receptor opens when the membrane potential is +60mV, will Na+ move into the cell or out of the cell? Extra credit (4 pts) Ion M+ has an equilibrium potential of -61mV. If the concentration of M+ outside of the cell were increased to 10 times its original value, what would the new equilibrium potential of M+ be?