42 notecards = 11 pages (4 cards per page)
In the figure above, which structure corresponds to a single skeletal muscle cell?
The connective tissue that covers structure A is continuous with which of the following?
Which structure corresponds to a single fascicle?
Which of the following is the smallest structural unit in which the distinctive striated bands characteristic of skeletal muscle are observed?
The smallest contractile unit within skeletal muscle would correspond to the distance between which two points in the figure?
1 and 7
Between which two points would there be substantial amounts of both the proteins actin and myosin?
2 and 3
The region between which two points corresponds to the entire A band?
2 and 6
The region between which two points corresponds to the I band?
None of the listed responses is correct.
What cellular event is indicated by A?
What event directly triggers the release of neurotransmitter shown in A?
diffusion of Ca2+ into the axonal terminus
What specific neurotransmitter is released from the axonal terminus as shown in A?
Which statement accurately describes the event indicated by B?
Binding of acetylcholine to a receptor triggers the opening of an ion channel.
Which event is most significant in initiating the "wave of depolarization" shown in event C?
diffusion of Na+ into the muscle fiber
The protein actin is indicated by which letter?
Which protein is indicated by E?
The molecular interaction described as a "cross bridge" involves the binding of which two of the letters below?
A and C
Which lettered protein functions as a motor protein?
The protein troponin is shown in this figure to be bound to which substance?
How many motor units are illustrated in the figure?
Which of the following describes the neurons shown in this figure?
somatic motor neurons
If both of the neurons in the figure were activated, more muscle fibers would contract than if either neuron alone were active. This mechanism for control of the force of muscle contraction is known as ______.
In which phase of the muscle twitch shown in the above figure would the maximum amount of ATP be consumed by myosin head groups?
In which phase in the figure would the net movement of Ca2+ into the sarcoplasmic reticulum (SR) be greatest?
What result would be expected if an additional stimulus, equal in intensity to the first, were to be applied to the muscle at the 60 millisecond (ms) time point?
The muscle would increase in tension to a level greater than that measured at the beginning of phase C.
Which mechanism requires energy input by the cell in the form of ATP hydrolysis?
none of the mechanisms require energy input
Which of the following events might the solid arrow at the bottom of B represent?
the activation of specific cytoplasmic enzymes
Which of the following is true regarding a response to an excitatory event which might occur soon after the initial stimulus indicated in the graph?
An excitatory event may result in an action potential, but this will be less likely if the excitatory stimulus occurs during the response to the stimulus observed in the graph.
What event is depicted in the structure labeled A?
movement of Ca2+ into the interior of the axonal terminus through voltage-gated channels
Which of the following most accurately describes the involvement of the structure labeled B in synaptic signaling?
release of neurotransmitter into the synaptic cleft by exocytosis
Which of the following statements most accurately describes the effects caused by binding of the ligand shown to the structure labeled C?
The membrane potential of the postsynaptic membrane changes.
The box labeled D illustrates three mechanisms by which the effects of a neurotransmitter may be terminated. Which of the following mechanisms is NOT included in the figure?
reuptake of the neurotransmitter by transport into the postsynaptic cell
Signals generated at a chemical synapse are said to move only in the direction of the presynaptic cell to the postsynaptic cell. Which of the following statements regarding the mechanisms determining this one way transmission is INCORRECT?
Ions diffusing out of the presynaptic cell can enter the postsynaptic cell, but cannot reenter the presynaptic cell.
In which area of the neuron is an action potential initially generated?
Which of the following membrane regions would have significant numbers of voltage-gated Na+ and K+ ion channels?
C and D
Which of the following statements is true of both membrane potential responses shown in the graphs?
Both responses are examples of graded potentials.
Which result of the stimulus applied is the likely cause of the response observed in the left graph?
opening of gated Na+ channels
Which of the following is expected to occur first if the membrane potential increase shown in the graph were to reach the threshold value indicated at -55 mV?
opening of voltage gated Na+ channels
What change in a neuron is being measured in the graph?
the voltage measured across the axon membrane at a specific point as an action potential travels past
At which point of the illustrated action potential are the most gated Na+ channels open?
What major ion currents occur at the point along the action potential phase labeled D?
diffusion of K+ out of the axon through gated ion channels
Which of the following mechanisms is most significant in returning the membrane potential to the resting state (from point D to point E)?
closure of the voltage-gated K+ channels
At which of the points along the illustrated action potential can a second action potential be produced, but only with a stimulus significantly greater than that which produced the first?