Section: Chapter 4: Multiple Choice

Transcription

1 Section: Chapter 4: Multiple Choice 1. Electricity is a flow of electrons from a body that contains a higher charge (more electrons) to a body that has a lower charge (fewer electrons). The body containing the higher electrical charge is called a: p.114 positive pole. negative pole. dipole. ground pole. 2. Another word for volts would be: electrical potential between two poles. current flow. amps. both b and c. p An electroencephalogram, or EEG, can theoretically be recorded by: a voltmeter. an oscilloscope. an ampmeter. both a and b. pp Neurons in most animals, including humans, are approximately: p to 20 thousandths of a millimeter in diameter. 50 to 100 thousandths of a millimeter in diameter. 500 to 700 thousandths of a millimeter in diameter. up to a millimeter in diameter. 1

2 5. Axons were first examined in squids because: giant squids have large axons. the axons were easy to dissect. squids have only one large axon. all of the above. p Microelectrodes can: be made from glass. be made from wire. have a tip as small as 0.001mm. all of the above. p The patch-clamp technique involves: placing the tip of a microelectrode on an axon. recording between two microelectrodes, one inside the axon and the other outside. placing the tip of the microelectrode in an axon and applying some back suction. placing the tips of the two microelectrodes in an axon and recording between them. p If a small amount of dye is placed in a beaker of water, it will flow away from the initial point of contact. The ensuing process illustrates: diffusion. concentration. charge. electrostatic. p Channels in the cell membrane are formed by: sodium ions. potassium ions. protein molecules. lipids. p.122 2

3 10. Which of the following is not involved in producing the resting potential? potassium ions chloride ions small protein anions sodium ions p The resting potential: is -70mV in all species. can vary from -40mV to -90mV within a species. can vary from -40mV to -90mV between species. none of the above. p Large protein anions are: manufactured by glial cells. manufactured within a neuron. transported to a neuron by glial cells. not part of a neuron. p The sodium/potassium pump: continuously exchanges three intracellular Na+ for two K+. continuously exchanges three intracellular K+ for two Na+. continuously exchanges three extracellular Na+ for two K+. intermittently exchanges three intracellular K+ for two Na+. p Which of the following is not true? The cell membrane is semi-permeable, so it keeps in large charged protein molecules. The membrane keeps out Na+ and allows K+ and C1- to pass more freely. The membrane has a sodium/potassium pump that extrudes potassium. The summed charges of the unequally distributed ions leave the inside of the membrane at -70mV relative to the outside. This is the cell's resting potential. pp

4 15. A change in the resting potential from -70mV to -73mV is called: depolarization. hyperpolarization. graded excitatory potential. nothing, as these changes occur spontaneously. p The use of tetrodotoxin (puffer fish poison) surrounding an axon demonstrates: the role of potassium channels in hyperpolarization. the role of sodium channels in depolarization. the role of potassium channels in depolarization. the role of sodium channels in hyperpolarization. p Tetraethylammonium (TEA): blocks potassium channels. blocks sodium channels. blocks chlorine channels. neutralizes large protein molecules. p An action potential is: a large graded potential. a large brief change in the polarity of a membrane. the same as a threshold potential. seldom shorter than 10 milliseconds. p During an action potential: the voltage of the cell membrane drops to 0 and then returns to -70mV. the voltage of the cell membrane drops to 0 and then returns to about -100mV and then to -70mV. the voltage of the cell membrane goes to about +30mV and then drops to -70mV. the voltage of the cell membrane goes to about +30mV and then drops to -100mV and then goes to -70mV. pp

5 20. Voltage-sensitive channels are active: whenever the cell membrane starts to depolarize. when the voltage across the membrane reaches 0mV. when the threshold voltage of the cell is reached. when the voltage across the membrane reaches +30mV. p A cell cannot produce an action potential: p.129 during the relative refractory period. during the absolute refractory period. when the resting potential voltage has not been reached. none of the above. 22. Refractory periods are due to: p.129 voltage-sensitive sodium and potassium channels. regular sodium and potassium channels. the time constraint on the sodium/potassium pump. chlorine not entering the membrane quickly enough. 23. "Nerve impulse" describes: p.130 an action potential crossing the synaptic cleft. input at the dendrites of a cell. the movement of an action potential along the axon. an action potential along the combined axons, which are called nerves. 24. An action potential goes only in one direction in an axon because: p.130 the ions can flow only in one direction. the refractory periods force the impulse to go in one direction. the ion flow is attracted to chemicals in the synaptic knob. autoreceptors inhibit backward flow of ions. 5

6 25. "Saltatory conduction" refers to: p.132 sodium concentration in the extracellular fluid. action potentials that are facilitated by sodium. action potentials jumping from one node to the next. the leakage of the sodium channels that require the existence of a sodium/potassium pump. 26. The fastest conduction occurs in: totally myelinated axons. partially myelinated axons. unmyelinated axons. both a and b. p Excitatory postsynaptic potentials (EPSP) are recorded: p.133 at the synaptic knob. in the axon. in the dendrites. in the cell body. 28. Dendrites can receive: excitatory input. inhibitory input. excitatory and inhibitory input from the same cell. both a and b. p Inhibitory postsynaptic potentials: p.133 are associated with the opening of potassium channels. are associated with the opening of sodium channels. are associated with the closing of potassium channels. are associated with the closing of sodium channels. 6

7 30. Stimulation producing two EPSPs in quick succession illustrates: spatial summation. temporal summation. both a and b. neither a nor b. p Spatial summation is more likely to occur: p.135 when the two impulses are far apart on the membrane. when the two impulses are close together on the membrane. without regard to distance on the membrane. when one EPSP follows the second by a short interval. 32. Action potentials originate in the: p.137 axon. dendrites. cell body. axon hillock. 33. EPSPs on the distant dendrites tree: p.137 have maximum influence on an action potential. are easier than EPSPs elsewhere to summate both spatially and temporally. are less likely to have a dynamic effect than those close to the axon hillock. do not modulate action potentials. 34. Alpha rhythms are recorded from: p.143 microelectrodes. evoked potentials. EEG. action potentials. 7

8 35. EEG is a measure of: graded potentials. evoked potentials. action potentials. event-related potentials. p EEG can be used to: pp monitor sleep. detect tumors. detect epilepsy. all of the above. 37. Event-related potentials pp are quite different from EEG. are summed action potentials. are summed EEGs. none of the above. 38. The most promising technique for studying development and aging is: p.148 EEG. single-cell recording. stimulation. ERP. 39. Myaesthenia gravis is: p.144 an autoimmune disease. more common in men than women. caused by a viral infection. caused by a bacterial infection. 8

9 40. Lou Gehrig's disease is also known as: p.140 multiple sclerosis. arteriosclerosis. amyotrophic lateral sclerosis. was formerly called poliomyelitis. 41. Seizures characterized by severe abnormalities of movement are termed: p Single cells: epileptic seizures. petit mal seizures. idiopathic seizures. grand mal seizures. communicate only when they are active. can respond to a particular human face. can respond to a particular human voice. both b and c. pp An end plate is found: p.141 on a muscle membrane. on a dendrite membrane. on an axon. on touch receptors. Answer Key 9