Npb101 - NPB101 SPRING 2002 MIDTERM#1 1 Which of the following statements best describes the blood-brain barrier and/or the cerebrospinal fluid a

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NPB101 SPRING 2002 MIDTERM #1 1. Which of the following statements best describes the blood-brain barrier and/or the cerebrospinal fluid? a. the blood-brain barrier is formed by the choroid epithelium and leaky capillaries. b. the blood-brain barrier allows water, proteins, positive ions, and negative ions to enter the cerebrospinal fluid. c. the cerebrospinal fluid is formed continuously, and ideally, the amount that is formed is matched by an amount that returns to the blood through a vein on the underside of the skull. 2. Which of the following statements best describes the role of leak permeabilities and the Na + -K + ATPase in forming resting potential? a. the resting potential of the spiking neurons described in class is due to a leak permeability to K + ions, and a smaller leak permeability to Na + ions. b. leak permeabilities are due to diffusion of K + and Na + ions through the lipid bilayer of cell membranes. c. the ATPase creates resting potential by pumping more positive ions out of cells than the amount of positive ions it pumps into cells. 3. Which of the following statements best describes similarities or differences between the Nernst and Goldman equations? a. ion permeabilities are factors in the Nernst equation (i.e., they are necessary to solve the Nernst equation). b. ion permeabilities are not factors in the Goldman equation (i.e., they are never needed to solve the Goldman equation). c. both equations include values of ion concentrations and temperature. d. both equations can describe how an increase in extracellular Na + ion concentration can depolarize a cell that is permeable only to K + ions. 4. Which of the following statements best describes events that occur during an action potential? a. during any moment that the membrane potential is 0 mV, there is no electrical force acting on Na + ions. b. after the peak of a spike, as the membrane potential changes from +20 mV to 0 mV, Na + ions stop entering the cell, and instead, they start to leave the cell. c. the membrane potential becomes more positive than 0 mV because Na + influx is large enough to make [Na + ] i larger than [Na + ] o . 5. When a cell is depolarized to spike threshold, . .. a.
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This note was uploaded on 08/09/2008 for the course NPB 101 taught by Professor Fuller,charles/goldberg,jack during the Spring '08 term at UC Davis.

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Npb101 - NPB101 SPRING 2002 MIDTERM#1 1 Which of the following statements best describes the blood-brain barrier and/or the cerebrospinal fluid a

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