Problem 1
What happens when a resting neuron's membrane depolarizes? a. There is a net diffusion of Na+ out of the cell. b. The equilibrium potential for K+(EK) becomes more positive. c. The neuron's membrane voltage becomes more positive. d. The cell's inside is more negative than the outside.
Problem 2
A common feature of action potentials is that they a. cause the membrane to hyperpolarize and then depolarize. b. can undergo temporal and spatial summation. c. are triggered by a depolarization that reaches threshold. d. move at the same speed along all axons.
Problem 3
Where are neurotransmitter receptors located? a. the nuclear membrane b. the nodes of Ranvier c. the postsynaptic membrane d. synaptic vesicle membranes
Problem 4
Why are action potentials usually conducted in one direction? a. Ions can flow along the axon in only one direction. b. The brief refractory period prevents reopening of voltage-gated Na+ channels. c. The axon hillock has a higher membrane potential than the terminals of the axon. d. Voltage-gated channels for both Na+ and K+ open in only one direction.
Problem 5
Which of the following is the most direct result of depolarizing the presynaptic membrane of an axon terminal? a. Voltage-gated calcium channels in the membrane open. b. Synaptic vesicles fuse with the membrane. c. Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft. d. An EPSP or IPSP is generated in the postsynaptic cell.
Problem 6
Suppose a particular neurotransmitter causes an IPSP in postsynaptic cell X and an EPSP in postsynaptic cell Y. A likely explanation is that a. the threshold value in the postsynaptic membrane is different for cell X and cell Y. b. the axon of cell X is myelinated, but that of cell Y is not. c. only cell Y produces an enzyme that terminates the activity of the neurotransmitter. d. cells X and Y express different receptor molecules for this particular neurotransmitter.
Ch. 48 - Neurons, Synapses, and Signaling
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