Question 1

The rate of _______ cross-bridge recycling is central to the difference between slow-twitch and fast-twitch fibers.

Accepted Answer

The answer of The rate of _______ cross-bridge recycling is...

Question 2

The three systems by which muscles obtain ATP

Accepted Answer

A)  differ in the capacity and rate at which they produce ATP. 
B)  rely on the large amounts of ATP already present in the muscle itself. 
C)  produce similar amounts of ATP. 
D)  rely on reactions within mitochondria. 
E)  have similar time courses. 
A)  differ in the capacity and rate at which they produce ATP. 
B)  rely on the large amounts of ATP already present in the muscle itself. 
C)  produce similar amounts of ATP. 
D)  rely on reactions within mitochondria. 
E)  have similar time courses.

Question 3

When ATP binds to myosin,

Accepted Answer

A)  the myosin head attaches to actin. 
B)  the myosin head releases actin. 
C)  calcium binds to troponin. 
D)  troponin changes conformation. 
E)  tropomyosin exposes actin-myosin binding sites. 
A)  the myosin head attaches to actin. 
B)  the myosin head releases actin. 
C)  calcium binds to troponin. 
D)  troponin changes conformation. 
E)  tropomyosin exposes actin-myosin binding sites.

Question 4

Anaerobic exercise such as weight lifting

Accepted Answer

A)  increases endurance without increasing strength. 
B)  causes damage to muscle, none of which can be repaired. 
C)  induces the formation of new actin and myosin filaments in existing muscle fibers. 
D)  produces smaller muscle fibers but increases their number and hence creates bigger muscles. 
E)  causes satellite cells to increase the number of intercalated discs between the muscle fibers. 
A)  increases endurance without increasing strength. 
B)  causes damage to muscle, none of which can be repaired. 
C)  induces the formation of new actin and myosin filaments in existing muscle fibers. 
D)  produces smaller muscle fibers but increases their number and hence creates bigger muscles. 
E)  causes satellite cells to increase the number of intercalated discs between the muscle fibers.

Question 5

Which statement about bone is true?

Accepted Answer

A)  Insoluble calcium carbonate crystals are in the extracellular matrix of bone. 
B)  Calcitonin and thyroxine regulate calcium levels in the bone and extracellular fluid. 
C)  Time spent in zero gravity causes bones to decalcify, while weight-bearing exercise increases bone deposition. 
D)  Bone remodeling occurs only while a young person is growing. 
E)  Bone is devoid of collagen fibers. 
A)  Insoluble calcium carbonate crystals are in the extracellular matrix of bone. 
B)  Calcitonin and thyroxine regulate calcium levels in the bone and extracellular fluid. 
C)  Time spent in zero gravity causes bones to decalcify, while weight-bearing exercise increases bone deposition. 
D)  Bone remodeling occurs only while a young person is growing. 
E)  Bone is devoid of collagen fibers.

Question 6

Which description characterizes Haversian systems?

Accepted Answer

A)  They are units within spongy bone. 
B)  They make up trabecular bone. 
C)  They have central canals with blood vessels and nerves. 
D)  They make bone weak due to their glue lines. 
E)  They consist of a set of concentric tubes perpendicular to the long axis of the bone. 
A)  They are units within spongy bone. 
B)  They make up trabecular bone. 
C)  They have central canals with blood vessels and nerves. 
D)  They make bone weak due to their glue lines. 
E)  They consist of a set of concentric tubes perpendicular to the long axis of the bone.

Question 7

The strength of contraction of a muscle can be increased by

Accepted Answer

A)  increasing the intensity of the action potential, only. 
B)  increasing the firing rate of an individual motor neuron, only. 
C)  recruiting additional motor neurons, only. 
D)  prolonging the action potential, only. 
E)  increasing the firing rate of an individual motor neuron and recruiting additional motor neurons. 
A)  increasing the intensity of the action potential, only. 
B)  increasing the firing rate of an individual motor neuron, only. 
C)  recruiting additional motor neurons, only. 
D)  prolonging the action potential, only. 
E)  increasing the firing rate of an individual motor neuron and recruiting additional motor neurons.

Question 8

Which statement about the immediate system for supplying ATP to muscle cells is true?

Accepted Answer

A)  The immediate system uses the very large amounts of ATP present in muscle cells. 
B)  The energy available from the immediate system is unlimited and instantly available. 
C)  The energy available from the immediate system enables slow-twitch fibers to generate a lot of force in a short amount of time. 
D)  The immediate system uses creatine phosphate as an energy source. 
E)  The energy available from the immediate system is slowly exhausted. 
A)  The immediate system uses the very large amounts of ATP present in muscle cells. 
B)  The energy available from the immediate system is unlimited and instantly available. 
C)  The energy available from the immediate system enables slow-twitch fibers to generate a lot of force in a short amount of time. 
D)  The immediate system uses creatine phosphate as an energy source. 
E)  The energy available from the immediate system is slowly exhausted.

Question 9

Osteoblasts are cells that

Accepted Answer

A)  lay down new matrix on bone surfaces. 
B)  are surrounded by matrix and remain in contact through thin cellular extensions. 
C)  sit in lacunae that are connected by tiny channels. 
D)  break down old bone and deposit new bone. 
E)  break down old cartilage and deposit new bone. 
A)  lay down new matrix on bone surfaces. 
B)  are surrounded by matrix and remain in contact through thin cellular extensions. 
C)  sit in lacunae that are connected by tiny channels. 
D)  break down old bone and deposit new bone. 
E)  break down old cartilage and deposit new bone.

Question 10

_______ muscle provides the contractile force for most of our internal organs, which are regulated by the autonomic nervous system.

Accepted Answer

The answer of _______ muscle provides the contractile force for...

Question 11

The minimum unit of contraction of a muscle fiber is

Accepted Answer

A)  a summation. 
B)  a tetanus. 
C)  a twitch. 
D)  a sustained contraction. 
E)  the smallest number of fibers in a motor unit. 
A)  a summation. 
B)  a tetanus. 
C)  a twitch. 
D)  a sustained contraction. 
E)  the smallest number of fibers in a motor unit.

Question 12

Refer to the figure of sarcomeres.   If panel A represents a sarcomere in a resting muscle, then panel B represents a sarcomere in a _______ muscle.

Accepted Answer

The answer of Refer to the figure of sarcomeres. ...

Question 13

Which statement about muscle cells is true?

Accepted Answer

A)  The plasma membrane of a muscle cell does not conduct action potentials. 
B)  A motor unit is a motor neuron and one of the muscle fibers with which it synapses. 
C)  A neuromuscular junction is the area of contact between the axon terminal of a motor neuron and a T tubule of a skeletal muscle cell. 
D)  An action potential in a muscle fiber travels into the T tubules of the muscle cell. 
E)  Each skeletal muscle has a single motor unit. 
A)  The plasma membrane of a muscle cell does not conduct action potentials. 
B)  A motor unit is a motor neuron and one of the muscle fibers with which it synapses. 
C)  A neuromuscular junction is the area of contact between the axon terminal of a motor neuron and a T tubule of a skeletal muscle cell. 
D)  An action potential in a muscle fiber travels into the T tubules of the muscle cell. 
E)  Each skeletal muscle has a single motor unit.

Question 14

When a person substitutes weight lifting for her daily jogging regimen there will be a consequent increase in the

Accepted Answer

A)  number of mitochondria in skeletal muscle cells. 
B)  amount of myoglobin in skeletal muscle cells. 
C)  enzymes involved in energy use. 
D)  density of capillaries supplying skeletal muscles. 
E)  size of muscle fibers. 
A)  number of mitochondria in skeletal muscle cells. 
B)  amount of myoglobin in skeletal muscle cells. 
C)  enzymes involved in energy use. 
D)  density of capillaries supplying skeletal muscles. 
E)  size of muscle fibers.

Question 15

Despite their lumbering appearance, alligators are capable of quick bursts of speed.This is most likely because their muscles

Accepted Answer

A)  fuel their rapid movement with high levels of mitochondria. 
B)  have surprisingly low rates of ATPase activity. 
C)  are slow-twitch muscles. 
D)  are fast-twitch muscles. 
E)  have substantial reserves of glycogen. 
A)  fuel their rapid movement with high levels of mitochondria. 
B)  have surprisingly low rates of ATPase activity. 
C)  are slow-twitch muscles. 
D)  are fast-twitch muscles. 
E)  have substantial reserves of glycogen.

Question 16

Which feature characterizes rigor mortis?

Accepted Answer

A)  Relaxing of muscles shortly after death 
B)  Results from a pre-death surge in ATP production 
C)  Permanence 
D)  Bonds between actin and myosin are not broken 
E)  Stops when the hydrolysis of muscle ATP causes myosin to release its attachment to actin 
A)  Relaxing of muscles shortly after death 
B)  Results from a pre-death surge in ATP production 
C)  Permanence 
D)  Bonds between actin and myosin are not broken 
E)  Stops when the hydrolysis of muscle ATP causes myosin to release its attachment to actin

Question 17

A major disadvantage of the glycolytic system for supplying ATP to muscle fibers is

Accepted Answer

A)  the efficiency of glycolysis compared to aerobic respiration. 
B)  the long period of time that is required before it can start supplying ATP. 
C)  that it leads to the accumulation of lactic acid. 
D)  that it requires numerous mitochondria. 
E)  that it requires a large supply of oxygen, and therefore a high density of capillaries 
A)  the efficiency of glycolysis compared to aerobic respiration. 
B)  the long period of time that is required before it can start supplying ATP. 
C)  that it leads to the accumulation of lactic acid. 
D)  that it requires numerous mitochondria. 
E)  that it requires a large supply of oxygen, and therefore a high density of capillaries

Question 18

Which statement pertaining to smooth muscle is true?

Accepted Answer

A)  It does not use a sliding filament contractile mechanism. 
B)  It creates movement in the gut. 
C)  Its cells are multinucleate. 
D)  It is responsible for the beating of the heart. 
E)  Its cells are connected by intercalated discs. 
A)  It does not use a sliding filament contractile mechanism. 
B)  It creates movement in the gut. 
C)  Its cells are multinucleate. 
D)  It is responsible for the beating of the heart. 
E)  Its cells are connected by intercalated discs.

Question 19

Muscle tone is the condition in which

Accepted Answer

A)  different muscles are taking responsibility for maintaining posture. 
B)  the muscle has generated maximum tension. 
C)  the muscle will eventually exhaust its supply of ATP. 
D)  a small but changing number of motor units are active in a muscle. 
E)  the maximum number of action potentials is being received by the muscle. 
A)  different muscles are taking responsibility for maintaining posture. 
B)  the muscle has generated maximum tension. 
C)  the muscle will eventually exhaust its supply of ATP. 
D)  a small but changing number of motor units are active in a muscle. 
E)  the maximum number of action potentials is being received by the muscle.

Question 20

How do muscle fibers shorten during contraction?

Accepted Answer

A)  Individual protein filaments contract. 
B)  Additional cross-bridges are formed between filaments. 
C)  Arrays of filaments overlap and slide past arrays of another type of filament. 
D)  Protein filaments coil more tightly. 
E)  Subunits of protein polymers detach themselves from the larger units. 
A)  Individual protein filaments contract. 
B)  Additional cross-bridges are formed between filaments. 
C)  Arrays of filaments overlap and slide past arrays of another type of filament. 
D)  Protein filaments coil more tightly. 
E)  Subunits of protein polymers detach themselves from the larger units.

Exam 47: Musculoskeletal Systems

The rate of _______ cross-bridge recycling is central to the difference between slow-twitch and fast-twitch fibers.

The three systems by which muscles obtain ATP

When ATP binds to myosin,

Anaerobic exercise such as weight lifting

Which statement about bone is true?

Which description characterizes Haversian systems?

The strength of contraction of a muscle can be increased by

Which statement about the immediate system for supplying ATP to muscle cells is true?

Osteoblasts are cells that

_______ muscle provides the contractile force for most of our internal organs, which are regulated by the autonomic nervous system.

The minimum unit of contraction of a muscle fiber is

Refer to the figure of sarcomeres. If panel A represents a sarcomere in a resting muscle, then panel B represents a sarcomere in a _______ muscle.

Which statement about muscle cells is true?

When a person substitutes weight lifting for her daily jogging regimen there will be a consequent increase in the

Despite their lumbering appearance, alligators are capable of quick bursts of speed.This is most likely because their muscles

Which feature characterizes rigor mortis?

A major disadvantage of the glycolytic system for supplying ATP to muscle fibers is

Which statement pertaining to smooth muscle is true?

Muscle tone is the condition in which

How do muscle fibers shorten during contraction?

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