Chapter 6. Synaptic & Junctional Transmission
A neurology resident was conducting research in an electrophysiology laboratory and was studying the roles of cation channels in mediating nonpropagated potentials. Which of the following electrophysiologic events is correctly paired with the change in ionic currents causing the event?
A. Fast inhibitory postsynaptic potentials (IPSPs) and closing of Cl− channels
B. Fast excitatory postsynaptic potentials (EPSPs) and an increase in Ca2+ conductance
C. Endplate potential and an increase in Na+ conductance
D. Excitatory junctional potentials and closure of voltage-gated K+ channels
E. Slow EPSPs and an increase in K+ conductance
A neurology resident was conducting research in an electrophysiology laboratory and was studying the functional anatomy of synaptic transmission. Which of the following physiologic processes is correctly paired with a structure?
A. Electrical transmission: synaptic cleft
B. Positive feedback inhibition: Renshaw cell
C. Synaptic vesicle docking and fusion: presynaptic nerve terminal
D. Endplate potential: muscarinic cholinergic receptor
E. Action potential initiation: axon hillock
A medical student was studying the passive membrane properties of neurons and their ability to affect the amplitude of an EPSP recorded from the neuron. She found that in one neuron, applying two stimuli separated by 25 ms to one presynaptic input induced two EPSPs of identical amplitude. In a second neuron, the same type of stimulation induced an EPSP followed an action potential. What can she conclude from this experiment?
A. The second neuron had a longer time constant than the first neuron.
B. The second neuron had a shorter time constant than the first neuron.
C. The second neuron had a longer length constant than the first neuron.
D. The second neuron had a shorter length constant than the first neuron.
A medical student was doing research in a laboratory that studies the neuromuscular junction. Which of the following events at the junction are listed in correct sequential order?
A. Motor neuron action potential, acetylcholine release, Na+ entry at the endplate
B. Ca2+ entry into the motor nerve terminal, Na+ entry at the endplate, muscle fiber action potential