Biology 241 - Accelerated General Human Physiology » Summer 2021 » Lab Q11

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Question #1
During the skeletal muscle simulation, a low-voltage electrical stimulus (0 or 0.1 volts) produced no response on the screen because:
A.   the evoked action potential was too small to produce a visible contraction.
B.   the stimulus did not stimulate any muscle fibers to threshold.
C.   the muscle contraction was too small to register.
D.   the stimulus must produce many action potentials in the muscle fibers to evoke a contraction.
Question #2
The latency period is the time:
A.   taken for a skeletal muscle to contract and relax.
B.   when cross-bridge cycling is taking place and the muscle is shortening.
C.   period between stimulation and the shortening of the skeletal muscle.
D.   period when the level of calcium in the cytoplasm is greater than at rest.
Question #3
When the muscle had weights attached and trying to contract, what was happening during the latency period:
A.   the muscle was not contracting.
B.   there was no tension in the tendon.
C.   the muscle was contracting isometrically.
D.   the muscle was lifting the weight.
Question #4
According to the Length-Tension relationship, maximum tension is produced in a skeletal muscle fiber when it is:
A.   shorter than resting length
B.   at or near resting length
C.   longer than resting length
D.   tension is constant at all muscle lengths
Question #5
During incomplete tetanus, the amount of tension increases above that seen with a single twitch because:
A.   maximum tension is achieved.
B.   the muscle twitches fuse into a single, maximum contraction.
C.   there is accumulation of calcium in the sarcoplasm.
D.   sarcoplasmic calcium levels drop.
Question #6
Why would the rate of muscle relaxation be slower after tetanus than after a single twitch?
A.   Cross-bridges are formed during relaxation.
B.   The contraction was larger, so the rate of relaxation would be slower.
C.   There is maximum amount of overlap between the thick and thin myofilaments.
D.   It takes time for the large amount of calcium in the sarcoplasm to be taken up by the sarcoplasmic reticulum.
Question #7
Match the terms with its definition. muscle twitch
A.   muscle response from a single action potential
B.   declining muscle force during a sustained contraction
Question #8
Match the terms with its definition. tetanus
A.   muscle response from a single action potential
B.   maximum muscle force
Question #9
Match the terms with its definition. latent period
A.   time between action potential stimulus and muscle activation
B.   maximum muscle force
Question #10
Match the terms with its definition. motor unit
A.   time between action potential stimulus and muscle activation
B.   a single motor nueron and all the muscle fibers it innervates
Question #11
Match the terms with its definition. recruitment
A.   a single motor nueron and all the muscle fibers it innervates
B.   adding more muscle units to complete a task
Question #12
Match the terms with its definition. fatigue
A.   adding more muscle units to complete a task
B.   declining muscle force during a sustained contraction
Question #13
The electromyogram (EMG) records:
A.   the movement of the contracting muscle.
B.   tension in the contracting muscle.
C.   electrical activity from the contracting muscle fibers.
D.   electrical activity from the lower motor neurons.
Question #14
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.   the same number of muscle fibers contracting.
B.   more muscle fibers contracting.
C.   fewer muscle fibers contracting.

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