ESS 345 HW EXAM QUESTIONS WITH COMPLETE
VERIFIED ANSWERS GRADED A++
myosin...
is found in the A band
During muscle contraction...
the H zone becomes smaller or disappears
The SR stores ____ when a muscle is relaxed and releases it for binding to ____
for contraction.
Ca2+, troponin
Binding of ____ to myosin permits cross-bridges ____ between actin and myosin.
ATP, detachment
At rest cross bridge interaction between actin and myosin in skeletal muscle is
directly blocked by ____
tropomyosin
The energy for power stroke during muscle contraction is provided by ____.
ATP
Which of the following is involved in the process of muscle relaxation?
(a and b)
a. Acetylcholinesterase detroys acetylcholine to allow the muscle membrane to return to
resting potential.
, b. Ca2+ is actively taken up by the lateral sacs of SR when there is no longer a local
action potential.
A motor unit refers to ____.
a single motor neuron and all the muscle fibers it innervates.
Twitch summation
(a and c)
a. is a means by which gradation of muscle contraction may be accomplished.
c. results from increasing the frequency at which motor units are firing within a muscle.
If you wanted to pick up something heavier than your pencil (such as your book),
you would need to have a stronger muscle contraction. In what way might you
accomplish this?
stimulate more motor units
If you want to hold a very heavy dumbbell to show your friends how strong you
are, you want to select the best joint angle____
(a and c)
a. where muscle length is optimal
c. where leverage is maximal
What is the energy-rich molecule that powers all biologic work?
ATP
(T/F)
Tetanus occurs when a muscle fiber is stimulated so rapidly that it is not allowed
to relax between stimulations, resulting in a smooth and sustained contraction.
True
VERIFIED ANSWERS GRADED A++
myosin...
is found in the A band
During muscle contraction...
the H zone becomes smaller or disappears
The SR stores ____ when a muscle is relaxed and releases it for binding to ____
for contraction.
Ca2+, troponin
Binding of ____ to myosin permits cross-bridges ____ between actin and myosin.
ATP, detachment
At rest cross bridge interaction between actin and myosin in skeletal muscle is
directly blocked by ____
tropomyosin
The energy for power stroke during muscle contraction is provided by ____.
ATP
Which of the following is involved in the process of muscle relaxation?
(a and b)
a. Acetylcholinesterase detroys acetylcholine to allow the muscle membrane to return to
resting potential.
, b. Ca2+ is actively taken up by the lateral sacs of SR when there is no longer a local
action potential.
A motor unit refers to ____.
a single motor neuron and all the muscle fibers it innervates.
Twitch summation
(a and c)
a. is a means by which gradation of muscle contraction may be accomplished.
c. results from increasing the frequency at which motor units are firing within a muscle.
If you wanted to pick up something heavier than your pencil (such as your book),
you would need to have a stronger muscle contraction. In what way might you
accomplish this?
stimulate more motor units
If you want to hold a very heavy dumbbell to show your friends how strong you
are, you want to select the best joint angle____
(a and c)
a. where muscle length is optimal
c. where leverage is maximal
What is the energy-rich molecule that powers all biologic work?
ATP
(T/F)
Tetanus occurs when a muscle fiber is stimulated so rapidly that it is not allowed
to relax between stimulations, resulting in a smooth and sustained contraction.
True
