Multi exam 3 Flashcards
Which property of muscle gives it the ability to stretch without damage?
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contractility
elasticity
extensibility
electrical excitability
extensibility
The outermost layer of connective tissue surrounding a skeletal muscle is the
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epimysium
perimysium
tendon
ligament
endomysium
epimysium
Which microscopic structure is found only in the cardiac muscle tissue?
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tropomyosin
sarcomeres
intercalated discs
striations
myosin
intercalated discs
Smooth muscle tone is maintained by the prolonged presence of [_____] in the muscle cell’s cytosol?
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ATP
acetylcholine
calcium ions
oxygen
sodium ions
calcium ions
Which type of muscle tissue is capable of undergoing the stress-relaxation response when stretched?
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single-unit smooth muscle fibers
cardiac muscle fibers
fast glycolytic fibers
fast oxidative-glycolytic fibers
multiunit smooth muscle fibers
single-unit smooth muscle fibers
In a neuromuscular junction, the effect of acetylcholine (ACh) binding to receptors on the motor end plate lasts only briefly due to
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endocytosis of the ACh receptor into the myofiber.
rapid destruction of ACh in the synaptic cleft by acetylcholinesterase.
rapid destruction of ACh in the synaptic cleft by monoamine oxidase.
diffusion of the ACh out of the synaptic cleft.
rapid uptake of the ACh into the myofiber.
rapid destruction of ACh in the synaptic cleft by acetylcholinesterase.
A small amount of muscle tension and muscle definition (the appearance of muscle beneath the skin) is present even in a relaxed muscle. A person who is physically fit due to regular exercise, will have more of this characteristic of muscle tissue than someone who is not fit. What is this characteristic?
Entry field with correct answer muscle contraction muscle tone muscle relaxation muscle refraction muscle recruitment
muscle tone
Smooth muscle fibers do not have striations like skeletal and cardiac muscle cells do. This is because:
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the sarcomeres are smaller than in cardiac muscle cells and skeletal fibers, and aren’t visible even when smooth muscle fibers are examined microscopically
smooth muscle fibers contain only intermediate filaments, which aren’t arranged in sarcomeres
smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres
visceral smooth muscle fibers don’t have striations, but multiunit smooth muscle cells do, but these cells are more rare, and so we rarely have a chance to view them with a microscope
smooth muscle fibers contain only intermediate filaments, which aren’t arranged in sarcomeres and visceral smooth muscle fibers don’t have striations, but multiunit smooth muscle cells do, but these cells are more rare, and so we rarely have a chance to view them with a microscope
smooth muscle fibers contain thin and thick filaments, as well as intermediate filaments, but none of them are arranged in sarcomeres
A large motor unit would control which body part?
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a muscle required for back support
a muscle of the finger
a muscle involved in facial features
all of these
a muscle required for back support
Choose the correct sequence of events:
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Action potential reaches synapse—Acetylcholine is released by motor neuron—Calcium ions enter motor neuron—Sodium ions flood into the muscle cell—Acetylcholine binds to gated ion channels on sarcolemma, transferring the action potential.
Action potential reaches synapse—Calcium ions enter motor neuron—Acetylcholine is released by motor neuron—Acetylcholine binds to gated ion channels on sarcolemma—Sodium ions flood into the muscle cell, transferring the action potential.
Action potential reaches synapse—Acetylcholine is released by motor neuron—Acetylcholine binds to gated ion channels on sarcolemma—Calcium ions enter motor neuron—Sodium ions flood into the muscle cell, transferring the action potential.
None of these.
Action potential reaches synapse—Calcium ions enter motor neuron—Acetylcholine is released by motor neuron—Acetylcholine binds to gated ion channels on sarcolemma—Sodium ions flood into the muscle cell, transferring the action potential.
A group of muscle cells stimulated by a single motor neuron is known as a
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motor unit.
neuron divergence.
myofibril.
contractile structure.
motor unit.
How are binding sites on actin exposed?
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Calcium ions attach to troponin which slides tropomyosin off binding sites on actin.
Contractile proteins from the transverse tubules attach to the binding sites on actin to fold them into their active configuration.
A pressure build up within the myofibril squeezes the binding sites into the active position.
ATP attaches to the binding sites to rotate them into the active position.
Calcium ions attach to troponin which slides tropomyosin off binding sites on actin.
What is the most common class of levers found in the body?
Entry field with correct answer first class lever second class lever third class lever
third class lever
The attachment of a muscle’s tendon to the stationary bone is called the _____; the attachment of the muscle’s other tendon to the movable bone is called the _____.
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origin, action
insertion, action
origin, insertion
insertion, origin
origin, insertion
The muscle that serves as the “prime mover” during a movement is called the
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antagonist.
agonist.
synergist.
asynergist.
fixator.
agonist
What features distinguish the three types of muscular tissue?
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microscopic anatomy
location
method of endocrine and nervous system control
all of the choices are correct
all of the choices are correct
Increasing the sarcomere length so that the actin and myosin do NOT touch results in an increase of tension during muscle contraction.
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True
False
False
A runner nearing the end of a marathon race would produce most ATP by:
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aerobic respiration.
anaerobic respiration.
creatine phosphate.
amino acid breakdown.
aerobic respiration.
Which of the following statements is INCORRECT?
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Concentric isotonic contractions result in muscle shortening.
Eccentric isotonic contractions result in controlled lengthening of the muscle.
Isometric contractions result in lengthening or shortening of the muscle and moving a load E large motor unit.
In isometric contractions, the tension generated is not great enough to move the load.
Isometric contractions result in lengthening or shortening of the muscle and moving a load E large motor unit.
Skeletal muscle fibers are classified as “fast” or “slow” based upon what factor?
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the number of mitochondria present
the amount of myoglobin present
the speed of the myosin ATPase
the ability of the muscle fiber to respond anaerobically
the speed of the myosin ATPase
Which type of muscular tissue has the highest capacity for regeneration?
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smooth muscle tissue
skeletal muscle tissue
cardiac muscle tissue
smooth muscle tissue
After the fusion of myoblasts, the muscle fiber loses its ability to
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lengthen
contract
grow
go through mitosis
go through mitosis
Which correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction?
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myofibrils, myofilaments, mitochondria
T tubules, sarcolemma, myofilament
muscle fiber, axon of neuron, myofibrils
sarcolemma, axon of neuron, T tubules
axon of neuron, sarcolemma, T tubules
axon of neuron, sarcolemma, T tubules
