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 stimulus must produce many action potentials in the muscle fibers to evoke a contraction.
B.   the muscle contraction was too small to register.
C.   the stimulus did not stimulate any muscle fibers to threshold.
D.   the evoked action potential was too small to produce a visible contraction.
Question #2
The latency period is the time:
A.   when cross-bridge cycling is taking place and the muscle is shortening.
B.   taken for a skeletal muscle to contract and relax.
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.   there was no tension in the tendon.
B.   the muscle was contracting isometrically.
C.   the muscle was lifting the weight.
D.   the muscle was not contracting.
Question #4
According to the Length-Tension relationship, maximum tension is produced in a skeletal muscle fiber when it is:
A.   at or near resting length
B.   longer than resting length
C.   shorter 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.   sarcoplasmic calcium levels drop.
C.   the muscle twitches fuse into a single, maximum contraction.
D.   there is accumulation of calcium in the sarcoplasm.
Question #6
Why would the rate of muscle relaxation be slower after tetanus than after a single twitch?
A.   There is maximum amount of overlap between the thick and thin myofilaments.
B.   The contraction was larger, so the rate of relaxation would be slower.
C.   Cross-bridges are formed during relaxation.
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.   maximum muscle force
B.   muscle response from a single action potential
Question #9
Match the terms with its definition. latent period
A.   maximum muscle force
B.   time between action potential stimulus and muscle activation
Question #10
Match the terms with its definition. motor unit
A.   a single motor nueron and all the muscle fibers it innervates
B.   time between action potential stimulus and muscle activation
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.   electrical activity from the lower motor neurons.
C.   electrical activity from the contracting muscle fibers.
D.   tension in the contracting muscle.
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.   more muscle fibers contracting.
B.   the same number of muscle fibers contracting.
C.   fewer muscle fibers contracting.

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