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
A low voltage electrical shock (0 or 0.1 volts) produced no response on the screen because:
A)the muscle contraction was too small to register.
B)the evoked action potential was too small to produce a visible contraction.
C)the shock must produce many action potentials in the muscle fibers to evoke a contraction.
D)the shock did not stimulate any muscle fibers to threshold for action potential production.
2
What was the lowest voltage setting required to produce a response on the screen, i.e., when the muscle tension value was greater than zero?
A)Zero volts.
B)Around 0.3 volts.
C)Around 1 volt.
D)Around 1.5 volts.
3
The smallest response you recorded, with a shock around 0.3 volts, was produced by:
A)a contraction of a small number of the fibers in the muscle.
B)a small contraction of all of the fibers in the muscle.
C)the shock having a direct effect on the transducer.
4
Increasing the shock voltage from about 0.3 to 1 volt increased the amount of tension produced by the muscle. This observation can be explained by:
A)an increase in the amount of contraction by all of the fibers in the muscle.
B)each fiber producing many contractions, so that the total muscle tension increased with increased voltage.
C)an increase in the number of contracting muscle fibers.
5
Tension increased with voltage, but then the amount of tension stayed approximately constant as the shock voltage was increased beyond a certain level which was:
A)at zero volts.
B)around 0.3 volts.
C)around 1 volt.
D)around 1.5 volts.
6
High voltage shocks produced a contraction that exhibited near-constant maximum tension. This can be explained as:
A)a single twitch-type contraction of all of the fibers in the muscle.
B)a brief burst of contractions of some of the fibers in the muscle.
C)a brief burst of contractions of all of the fibers in the muscle.
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
In the living frog, 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
In the living frog, recruitment of motor units into the contraction response is achieved by:
A)stimulating more muscle fibers.
B)stimulating more motor neurons.
C)increasing the reflex.
10
In the living frog, stimulation of spinal motor neurons is achieved by:
A)activation via the upper motor neurons.
B)activation from spinal motor neurons to the same muscle.
C)activation from spinal motor neurons to the antagonistic muscle.
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