Hole's Human Anatomy & Physiology (Shier), 12th Edition

Ph.I.L.S. 3.0 Quizzing 25: Ph.I.L.S. 3.0 Quizzing

Ph.I.L.S. 3.0 Quizzing

1
The electromyogram (EMG) records:
A)the movement of the contracting muscle.
B)action potentials from the motor neurons.
C)action potentials from the contracting muscle fibers.
D)tension in the contracting muscle.
2
You recorded an EMG (red trace) and a hand movement (blue trace). In this recording system, an event displayed on the screen to the left takes place before an event to the right. In your recordings
A)the EMG was recorded after the hand movement.
B)the EMG was recorded at the same time as the hand movement.
C)the EMG was recorded before the hand movement.
3
Assume that a 'twitch' involves a single contraction of some portion of the fibers in the muscle. What happens to the amount of muscle tension when the number of contracting muscle fibers increases?
A)The tension increases.
B)The tension stays the same.
C)The tension decreases.
4
In this lab, a muscle contraction created pressure in the hand dynamometer. When compared with a small response, the larger dynamometer signal was created by:
A)more muscle fibers were contracting.
B)the same number of muscle fibers were contracting.
C)fewer muscle fibers were contracting.
5
According to your data, an increase in EMG amplitude was correlated with:
A)a decrease in dynamometer pressure.
B)an increase in dynamometer pressure.
C)no change in dynamometer pressure.
6
If the peak-to-peak amplitude of the EMG is an indication of the number of muscle fibers contracting, an increase in dynamometer pressure was produced by:
A)more muscle fibers contracting.
B)the same number of muscle fibers contracting.
C)fewer muscle fibers contracting.
7
The term 'motor unit' refers to:
A)a motor neuron that supplies a group of muscle fibers.
B)the motor neurons that supply a skeletal muscle.
C)the muscle fibers in the skeletal muscle.
D)a motor neuron and the muscle fibers it supplies.
8
Increasing the number of active motor units:
A)produces a stronger contraction in the same population of muscle fibers.
B)produces multiple contractions in the same population of muscle fibers.
C)makes more muscle fibers contract.
9
Upper motor neurons recruit more motor units into a contraction response by:
A)stimulating more muscle fibers.
B)stimulating more motor neurons.
C)increasing the reflex.
10
In this lab an increase in dynamometer pressure was produced by:
A)activation of more motor neurons.
B)activation of more motor units.
C)contraction of more muscle fibers.
D)all of the above.
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