1. The lipid bilayer of the cell membrane… a. is due primarily to the presence of cholesterol. b. is due to the presence of hydrophilic and hydrophobic groups on the membrane’s triglycerides. * c. is formed as a result of the arrangement of phosphate and fatty acid groupings in the membrane’s phospholipids. d. is the result of translational movement of membrane proteins. e. b and c. 2. The establishment of a Gibbs-Donnan equilibrium across a semi-permeable membrane… * a. reflects the point at which the force of diffusion of an ion to which the membrane is permeable is exactly offset by the force of attraction of that ion by the counterion to which the membrane is not permeable. b. results in a voltage across the membrane that can be accurately predicted by the Nernst Equation for up to three permeant ions. c. is possible only if an active pump mechanism is functioning, even in an artificial membrane. d. a and b. e. None of the above. 3. An artificial membrane is highly permeable to Cl- and completely impermeable to its counterion K+. The concentration of KCl on one side of the membrane is 75 mM and on the other is 10 mM. The potential difference generated across the membrane at 25oC will be… * a. less than 58 mV. b. greater than 58 mV. c. zero. d. negative. e. b and d. 4. You are experimenting with a neuron in the laboratory. The neuron is immersed in a solution that is identical to normal extracellular fluid. Decreasing the internal concentration of K+ will… * a. decrease resting membrane potential. b. increase resting membrane potential. c. not affect resting membrane potential. d. hyperpolarize the cell. e. b and d.5. A person suffers from a strange disease whereby his neurons have no voltage- sensitive potassium channels. As a consequence… a. the rate at which an action potential reaches its peak would be slower than normal. b. there would be no absolute refractory period. c. following generation of an action potential, recovery to normal resting membrane potential would be faster than normal. * d. following generation of an action potential, recovery to normal resting membrane potential would be slower than normal. e. a and c. 6. In the laboratory, you record action potentials while a neuron is immersed in a physiological saline solution. You find that the amplitude of the action potentials decreases as you lower the external sodium concentration. a. This observation is impossible because it would be a violation of the all- or-none law for action potentials. b. This couldn’t happen because, if anything, decreasing external sodium concentration would make the amplitude of the action potentials greater. * c. This is a perfectly understandable observation because the amplitude of the action potential is determined, in part, by the concentration gradient for sodium. d. This could happen, but only if the neuron is generating compound action potentials. e. None of the above. 7. The myelin sheath… a. is characterized by high resistance internodes and low resistance nodes. b. is characteristic of neurons that conduct action potentials at relatively high velocities. c. is comprised of a lipid material. d. b and c. * e. a, b and c. 8. A neurotransmitter that interacts with a receptor on the subsynaptic membrane to cause only an increase in potassium permeability would… * a. have the same influence on postsynaptic membrane potential as GABA. b. generate either an EPP or an EPSP, depending on the nature of the postsynaptic cell. c. be released only by excitatory neurons. d. have no influence on the postsynaptic cell. e. None of the above.9 Voltage-sensitive calcium channels… a. are essential for chemical neurotransmission. b. are opened by the arrival of an action potential at the axon terminal. c. allow the entry of calcium ions into the region of the synaptic knob or terminal bouton. d. are necessary for successful exocytosis of synaptic vesicles. * e. All of the above. 10. The frequency with which a neuron generates action potentials… a. is limited by the absolute refractory period. b. increases in the course of temporal summation. c. is the basic element in spatial summation. d. is directly proportional to the amplitude of its action potential. * e. a and b. 11. The EPSP… a. is a potential change that reflects a depolarization of the subsynaptic membrane. b. will be an inhibitory event if the neurotransmitter that generates it is inhibitory. c. is a graded potential change that can vary in amplitude. d. will always be the same size since the action potential that generates it will always be the same size. * e. a and c. 12. Depending on the level at which the damage occurred, damage to the dorsal root ganglion on the right side of the spinal cord might… a. interfere with the ability to withdraw the left hand from a hot stove. b. prevent voluntary movement of the right hand. c. interfere with perception of warmth on the left big toe. * d. interfere with perception of warmth on the right foot. e. b and d. 13. Which of the following is NOT true with respect to spinal reflexes? a. Spinal reflexes save valuable time by eliminating all synaptic delay. b. The brain is completely isolated from the neurons involved in acute spinal reflex pathways. c. All spinal reflexes function to protect the organism from harmful stimuli. d. Spinal reflexes increase conduction velocity in the neuron. * e. All of the above, i.e., all of the above are not true.14. Which of the following is an appropriate anatomical relationship? a. cerebellum - myelencephalon b. hypothalamus - telencephalon c. medulla oblongata - mesencephalon d. diencephalon - brainstem * e. None of the above. 15. Chemical synapses… a. are unidirectional because of the absolute refractory period. b. depend on the presence of receptors which interact with neurotransmitter molecules to open voltage-sensitive channels on the subsynaptic membrane. c. have evolved in higher organisms because they are faster than electrical synapses. d. depend on an energy dependent active transport mechanism to move neurotransmitter across the synaptic cleft to the subsynaptic membrane. *