Quiz 8: Muscular System

Endomysium separates individual muscle fibers from each other.

An isotonic contraction is one that involves a change in length but not a change in tension.

In the initiation ofmuscle contraction, calcium ions bind totropomyosin, exposing active sites on actin for cross-bridge formation.

The enzyme ATPase is located in the heads of myosin molecules.

Acetylcholine released by a motor neuron crosses the synaptic cleft and reaches the motor end plate by diffusion.

ATP is necessary for muscle relaxation.

Cardiac muscle is located in the walls of blood vessels.

The muscle most responsible for a particular movement is called the prime mover or antagonist.

Troponin, tropomyosin and actin are all parts of the thin filaments.

Acetylcholinesterase breaks down the cross-bridge linkages between myosin to actin.

During the process of glycolysis, the breakdown of one glucose molecules results in production of two ATP molecules.

Muscle fatigue results from a combination of insufficient calcium and an excessof acetylcholine.

If frequency of stimulation to a muscle fiber is increased, the force of contraction will increase.

Recruitment refers to increasing the number of motor units involved in a muscle contraction.

Intercalated discs are found in skeletal muscle and cardiac muscle, but are not present in smooth muscle.

Endomysium separates individual muscle fibers from each other.

An isotonic contraction is one that involves a change in length but not a change in tension.

In the initiation ofmuscle contraction, calcium ions bind totropomyosin, exposing active sites on actin for cross-bridge formation.

The enzyme ATPase is located in the heads of myosin molecules.

Acetylcholine released by a motor neuron crosses the synaptic cleft and reaches the motor end plate by diffusion.

ATP is necessary for muscle relaxation.

Cardiac muscle is located in the walls of blood vessels.

The muscle most responsible for a particular movement is called the prime mover or antagonist.

Troponin, tropomyosin and actin are all parts of the thin filaments.

Acetylcholinesterase breaks down the cross-bridge linkages between myosin to actin.

During the process of glycolysis, the breakdown of one glucose molecules results in production of two ATP molecules.

Muscle fatigue results from a combination of insufficient calcium and an excessof acetylcholine.

If frequency of stimulation to a muscle fiber is increased, the force of contraction will increase.

Recruitment refers to increasing the number of motor units involved in a muscle contraction.

Intercalated discs are found in skeletal muscle and cardiac muscle, but are not present in smooth muscle. A) Part of the sarcoplasmic reticulum B) Group of fascicles C) Group of myofibrils D) Unit within a myofibril

What forms the myofibrils of skeletal muscle cells? A) Actin and myosin B) ATP and ADP C) Troponin and tropomyosin D) Fascia and tendons E) Perimysium and endomysium

What structures form a motor unit? A) Several motor neurons and one muscle fiber B) One motor neuronand several muscle fibers C) Several motor neurons and several muscle fibers

By what means does an electrical impulse travel deep into a skeletal muscle fiber in order to trigger a contraction? A) Via the sarcoplasmic reticulum B) Via transverse tubules C) Via mitochondria D) Via motor end plates E) Via gap junctions

Where are the vesicles that contain neurotransmitter molecules located? A) Within sarcoplasmic reticulum B) In synaptic cleft C) On motor end plate membranes D) In cytoplasm of motor neuron axon E) At boundaries of sarcomeres

What is the action of the enzyme acetylcholinesterase? A) Needed for acetylcholine bind to troponin B) Causes secretion of acetylcholine into synaptic cleft C) Breaks down acetylcholine D) Forms cross-bridge between acetylcholine molecules and acetylcholine receptors E) Stimulates production of acetylcholine within synaptic vesicles

How is creatine phosphate used by muscle cells? A) It causes the decomposition of ATP. B) It forms part of the thin filaments. C) It is used to regenerate ATP. D) It supplies energy for the breakdown ofATP to ADP. E) It breaks down acetylcholine, allowing relaxation to occur.

What binds to actin at its binding sites, allowing the formation of cross-bridges? A) ATP B) Myosin C) Troponin D) Tropomyosin E) Creatine

What is oxygen debt? A) The oxygen needed to oxidize one molecule of glucose during aerobic cellular respiration B) The oxygen needed after strenuous exercise to restore ATP and oxygen levels, and for liver cells to convert lactate to glucose C) The oxygen needed to begin a bout of strenuous exercise, starting from rest D) The oxygen needed to drive glycolysis in muscle and liver cells E) The oxygen needed to convert pyruvic acid to lactic acid to lactate

What is an example of a partial but sustained contraction of a whole muscle? A) Blinking an eyelid B) Tetanic contraction C) Muscle twitch D) Maintenance of posture E) Motor unit fatigue

The characteristic reddish color of skeletal muscle is due to the presence of what substance? A) Actin B) Myosin C) Myoglobin D) Calcium E) Glycogen

What is a threshold stimulus? A) Minimum strength of stimulus required to cause muscle fiber contraction to occur B) Maximal amount of force a muscle can exert C) Amount of oxygen needed for repeated contractions D) Minimal amount of force a muscle can exert E) Maximal amount of stimulation a muscle can withstand

What causes the rigor mortis that occurs in skeletal muscles after death? A) Increase in available ATP, and decreased membrane permeability to calcium ions B) Decrease in available ATP, and increased membrane permeability to calcium ions C) Persistent stimulation by motor neuron D) Decrease in the number of muscle fibers E) Increase in membrane leakiness to sodium, resulting in continuing action potentials

What term refers to the increase in the number of motor units activated as a result ofmore intensestimulation? A) Twitch B) Recruitment C) Threshold stimulation D) All-or-none response E) Summation

The muscles of the back that help maintain upright posture while standing still are undergoing what type of contractions? A) Isotonic contractions B) Isometric contractions

Activities such as distance swimming and distance running are most likely to stimulate the development of what type of muscle fiber? A) Slow fibers B) Fast fibers

What happens to a muscle that has lost its innervation? A) It undergoes hypertrophy. B) It stimulates the formation of new motor neurons. C) It undergoes atrophy. D) The muscle fibers enlarge in order to still undergo contraction.

Which statement describes multiunit smooth muscle? A) Composed of sheets of muscle cells B) Displays rhythmicity C) Found within the walls of the stomach and intestines D) Responds to stimulation by neurons and certain hormones

Compared to skeletal muscle, smooth muscle contracts __________ and relaxes __________. A) more slowly; more slowly B) more slowly; more rapidly C) more rapidly; more slowly D) more rapidly; more rapidly

What term refers to the attachment point for the movable end of the muscle? A) Origin B) Fulcrum C) Insertion D) Motor end plate E) Source

What term describes the muscle that is primarily responsible for opposing a particular action? A) Antagonist B) Prime mover C) Synergist D) Agonist

In muscle anatomy, what is an origin? A) The less movable end of a muscle B) The more movable end of the muscle C) The point of attachment of a tendon to a muscle D) The location of a neuromuscular junction E) The boundary between neighboring sarcomeres

A(n) __________ is a bundle of dense connective tissue that connects a skeletal muscle to a bone. A) origin B) insertion C) tendon D) ligament E) epimysium

Where would an antagonist to the sternocleidomastoidmuscles be located? A) On the posterior side of the body B) On the anterior side of the body C) Inferior to the clavicle

What statement describes the zygomaticusmuscle? A) It inserts on the coronoidprocess of the mandible. B) It elevates the corner of the mouth. C) It brings the head into an upright position. D) It closes the lips.

What is an action of the rectus femoris muscle? A) Extends leg at knee B) Plantar flexes the foot C) Extends the thigh at the hip D) Adducts the thigh

Layers of dense connective tissue called __________ separate and support individual muscles. A) fascia B) tendons C) cartilage D) aponeuroses

What are fascicles? A) Bundles of muscle fibers B) Bundles of collagen fibers C) Bundles of myofibrils D) Bundles of thick and thin filaments E) Bundles of smooth muscle cells

What is an alternate name for a skeletal muscle cell? A) Myofibril B) Myofilament C) Myosin D) Muscle fiber

In skeletal muscle, the thick filaments are mainly composed of ___________. A) myosin B) actin C) myofibrils D) sarcoplasm E) Z lines

What structures consist of actin and myosin filaments? A) Myofibrils B) T tubules C) Aponeuroses D) Fascicles E) Thick filaments

Skeletal muscle cells appear striated because of the presence of what parallel bundles? A) Sarcomeres B) Z lines C) Myosin D) Myofibrils E) Transverse tubules

What is the main component of thin filaments? A) Myofibrils B) Acetylcholine C) Actin D) Myosin E) Collagen

What structure within a skeletal muscle cell extends from Z line to Z line? A) Sarcolemma B) Sarcomere C) Sarcoplasmic reticulum D) A band E) I band

Name the membranouschannels or tunnels that extend inward from A) Sarcomeres B) Myofibrils C) Transverse tubules D) Cisternae E) Motor end plates

Enlarged portions of the sarcoplasmic reticulum are called __________. A) synaptic clefts B) cisternae C) H zones D) T tubules E) motor end plates

What type of neurons function to control effectors? A) Aerobic neurons B) Sensory neurons C) Axon terminals D) Motor neurons E) Motor units

What is the name of the functional connection between a motor neuron and a muscle cell? A) Motor end plate B) Synaptic cleft C) Synaptic vesicle D) Junctional plate E) Neuromuscular junction

The __________ is the gap that separates a muscle cell membrane from the neuron cell membrane in a neuromuscular junction. A) synaptic cleft B) T tubule C) motor end plate D) synaptic vesicle E) sarcoplasm

Following stenuous exercise, levels of ATP, creatine phosphate, oxygen, and glucose must be returned to normal levels. This situation, called __________, may take several hours to complete. A) oxygen debt B) muscle atrophy C) aerobic respiration D) tetany

Motor neurons communicate with muscle cells by releasing chemicals called ____________. A) neurotransmitters B) proteins C) myosin D) troponin E) tropomyosin

What is a description of the region known as the motor end plate? A) It has many openings leading into transverse tubules. B) Mitochondria are abundant. C) Synaptic vesicles are abundant. D) It functions to release neurotransmitter molecules.

What enzyme catalyzes the breakdown of the neurotransmitter used to stimulate skeletal muscle? A) Tropomyosin B) ATPase C) Acetylcholinesterase D) Norephinephrine

What neurotransmitter is used to stimulate skeletal muscle contraction? A) Norepinephrine B) Actin C) Acetylcholine D) Tropomyosin E) ATP

When acetylcholine binds to its receptors at the motor end plate, the muscle fiber membrane becomes more permeable to __________. A) potassium B) sodium C) calcium D) acetylcholine E) acetylcholinesterase

What is the effect of an increased concentration of calcium ion in the sarcoplasm? A) Actin binding sites become exposed. B) Myosin binding sites become exposed. C) Troponin binding sites become exposed. D) Actin and myosin become unable to accomplish contraction.

In skeletal muscle cells, what molecule can be used to transfer energy to ADP in order to form ATP? A) Acetylcholine B) Troponin C) Actin D) Creatinephosphate E) Glucose

In the absence of oxygen, what process is used by muscle cells to generate small amounts of ATP? A) Electron transport chain B) Glycolysis C) Aerobic respiration D) Hydrolysis of myoglobin

What is the product of the anaerobic breakdown of glucose? A) Creatine phosphate B) Pyruvic acid C) Carbon dioxide D) Water and ATP

What is the product of the aerobic breakdown of glucose? A) Creatine phosphate B) Pyruvic acid C) Lactic acid D) Carbon dioxide, water, and ATP

What molecule, only present in muscle cells, is used to temporarily store oxygen for use in aerobic respiration? A) Myoglobin B) Acetylcholine C) Creatine phosphate D) Lactic acid E) Pyruvic acid

After death, rigor mortis develops as levels of calcium in the sarcoplasm increase and levels of __________ decrease. A) ATP B) ADP C) sodium D) potassium E) myoglobin

A(n) __________ is a single contraction of a muscle fiber in response to a single stimulus. A) sustained contraction B) threshold stimulus C) twitch D) cramp E) all-or-none response

What muscle can act as a prime mover for plantar flexion of the foot? A) Gastrocnemius B) Tibialis anterior C) Extensor digitorum longus D) Biceps femoris

What results when a muscle fiber is stimulated repeatedly at a fast enough pace that, though it starts to relax between stimuli, it cannot completely relax between contractions? A) Muscle fatigue B) Complete tetaniccontraction C) Summation D) Peristalsis E) Recruitment

What is formed by a motor neuron and all the muscle cells it stimulates? A) Neuromuscular bundle B) Fascicle C) Motor unit D) Myofibril E) Motor end plate

Small, sustained contractions that are the result of repeated nervous stimulation, originating from the spinal cord and stimulating only a few muscle fibers at a time, is called __________. A) muscle tone B) tetanus C) summation D) a myogram E) a twitch

What type of muscle cell has a sarcoplasmic reticulum that is not well developed? A) Cardiac muscle cell B) Skeletal muscle cell C) Smooth muscle cell

What type of smooth muscle consists of muscle fibers that are separate rather than organized into sheets? A) Multiunit smooth muscle B) Visceral smooth muscle C) Skeletal muscle D) Cardiac muscle

What is peristalsis? A) A single contraction in response to a single stimulus of a muscle fiber B) A sustained contraction of a muscle fiber C) Wavelike smooth muscle contraction D) Contraction of progressively more motor units as stimulation strength increases E) The smallest strength of stimulus that will trigger a contraction of skeletal muscle fibers

What type of smooth muscle is found in the wall of the stomach? A) Striated muscle B) Visceral muscle C) Multiunit muscle D) Intercalated muscle

Consider the components of the lever that causes the flexion of the upper limb at the elbow. The fulcrum of the lever is the __________ and the force to move the rigid bar (the forearm bones) is provided by contraction of the __________. A) elbow joint; biceps brachii B) shoulder joint; triceps brachii C) elbow joint; triceps brachii D) shoulder joint; biceps brachii

For the biceps brachii, triceps brachii, and the quadriceps femoris, what is referred to by the prefixes "bi-", "tri-", and "quad-"? A) The number of heads (origins) B) The number of bones that are moved when the muscle contracts C) The number of insertions D) The number of aponeuroses bundling the muscles together

Using the muscle name as a clue, where is the tibialis posterior muscle located? A) At the buttocks B) At the back of the calf C) At the back of the arm D) Over the top of the foot E) Deep to the shoulder blade

Curare is a poison that binds to acetycholine receptors at the motor end plate. What is the result of curare poisoning? A) Increased acetylcholine production B) Lack of neurotransmitter release by the motor neuron C) Inability of the muscle fiber to respond to nervous stimulation D) Rapid breakdown of acetylcholine by acetylcholinesterase

The connective tissue covering that separates a muscle into fascicles is called the __________. A) perimysium B) endomysium C) epimysium

What is the effect of ATP binding to myosin? A) Cross-bridges form B) Cross-bridges break C) Troponin and tropomyosin interact to expose binding sites on actin D) Thin filaments become shorter, causing shortening of the sarcomere

In skeletal muscle fibers, what is the source of the calcium ions that are released into the sarcoplasm to bind with troponin, resulting in contraction? A) Extracellular fluid B) Sarcoplasmic reticulum C) Mitochondria D) Golgi apparatus

What type of muscle fiber is large in diameter and contains abundant glycogen and relatively few mitochondria? A) Fast fibers B) Slow fibers

With training, what changes will occur in the muscles of the lower limbs of a marathon runner? A) Development of more extensive capillary networks; cells develop more mitochondria B) Formation of more actin and myosin, causing enlargement of muscle fibers C) Loss of myoglobin and reduction in size of muscle fibers D) Drastic increase in number of muscle fibers

What type of muscle fiber will be more resistant to fatigue? A) Fast fiber B) Slow fiber

What is muscle atrophy? A) Decrease in size and strength B) Increase in number of muscle fibers C) Increase in size of muscle fibers D) Decrease in length of muscle fibers

As you go to lift your backpack off of the floor, there is a period of time when the muscles of your arm and back are contracting but your backpack has yet to move. The muscles are developing tension before they begin to shorten and before the bag begins to be lifted. This type of contraction is called an __________ contraction. A) isotonic B) isometric

A muscle that will adduct the thigh (moving it toward the midline of the body) will be located in what area? A) Inner thigh B) Buttocks C) Front of thigh D) Back of calf

Which two muscles share the same primary action? A) Temporalis and masseter B) Levator scapulae and pectoralis minor C) Supinator and pronator teres D) Biceps femoris and rectus femoris

Which muscles share the same primary action? A) Gluteus maximus and iliacus B) Gastrocnemius and soleus C) Zygomaticus and platysma D) Brachialis and triceps brachii

Using the muscle name as a clue, what is the action of the extensor carpi ulnaris? A) To extend the wrist B) To extend the arm at the shoulder C) To dorsiflex the foot D) To extend the leg at the knee

Consider a muscle that originates on the posterior femur and inserts on the posterior tibia. What is the action of this muscle? A) To flex the knee B) To flex the hip C) To extend the knee D) To extend the hip

Consider a muscle that originates on the anterior forearm and inserts on the palm of the hand. What is the action of this muscle? A) To flex the wrist B) To flex the elbow C) To extend the wrist D) To extend the elbow

Myasthenia gravis is an autoimmune disease in which an individual's own immune system produces antibodies to acetylcholine receptors, blocking or destroying them. What would be a major symptom of this disease? A) Muscle weakness B) Muscle spasms or cramps C) Hypertrophy of affected muscles D) Loss of motor neuron function

During the motion that extends the upper limb at the elbow, the triceps brachii represents which part of the lever? A) Rigid bar B) Fulcrum C) Force D) Resistance E) Handle

During the motion that extends the upper limb at the elbow, the elbow joint represents which part of the lever? A) Rigid bar B) Fulcrum C) Force D) Resistance E) Handle

Which of the following is NOT a basic component of a lever? A) Rigid bar B) Fulcrum C) Force D) Handle E) Resistance

What is a sarcomere? A) Part of the sarcoplasmic reticulum B) Group of fascicles C) Group of myofibrils D) Unit within a myofibril

What forms the myofibrils of skeletal muscle cells? A) Actin and myosin B) ATP and ADP C) Troponin and tropomyosin D) Fascia and tendons E) Perimysium and endomysium

What structures form a motor unit? A) Several motor neurons and one muscle fiber B) One motor neuronand several muscle fibers C) Several motor neurons and several muscle fibers

By what means does an electrical impulse travel deep into a skeletal muscle fiber in order to trigger a contraction? A) Via the sarcoplasmic reticulum B) Via transverse tubules C) Via mitochondria D) Via motor end plates E) Via gap junctions

Where are the vesicles that contain neurotransmitter molecules located? A) Within sarcoplasmic reticulum B) In synaptic cleft C) On motor end plate membranes D) In cytoplasm of motor neuron axon E) At boundaries of sarcomeres

What is the action of the enzyme acetylcholinesterase? A) Needed for acetylcholine bind to troponin B) Causes secretion of acetylcholine into synaptic cleft C) Breaks down acetylcholine D) Forms cross-bridge between acetylcholine molecules and acetylcholine receptors E) Stimulates production of acetylcholine within synaptic vesicles

How is creatine phosphate used by muscle cells? A) It causes the decomposition of ATP. B) It forms part of the thin filaments. C) It is used to regenerate ATP. D) It supplies energy for the breakdown ofATP to ADP. E) It breaks down acetylcholine, allowing relaxation to occur.

What binds to actin at its binding sites, allowing the formation of cross-bridges? A) ATP B) Myosin C) Troponin D) Tropomyosin E) Creatine

What is oxygen debt? A) The oxygen needed to oxidize one molecule of glucose during aerobic cellular respiration B) The oxygen needed after strenuous exercise to restore ATP and oxygen levels, and for liver cells to convert lactate to glucose C) The oxygen needed to begin a bout of strenuous exercise, starting from rest D) The oxygen needed to drive glycolysis in muscle and liver cells E) The oxygen needed to convert pyruvic acid to lactic acid to lactate

What is an example of a partial but sustained contraction of a whole muscle? A) Blinking an eyelid B) Tetanic contraction C) Muscle twitch D) Maintenance of posture E) Motor unit fatigue

The characteristic reddish color of skeletal muscle is due to the presence of what substance? A) Actin B) Myosin C) Myoglobin D) Calcium E) Glycogen

What is a threshold stimulus? A) Minimum strength of stimulus required to cause muscle fiber contraction to occur B) Maximal amount of force a muscle can exert C) Amount of oxygen needed for repeated contractions D) Minimal amount of force a muscle can exert E) Maximal amount of stimulation a muscle can withstand

What causes the rigor mortis that occurs in skeletal muscles after death? A) Increase in available ATP, and decreased membrane permeability to calcium ions B) Decrease in available ATP, and increased membrane permeability to calcium ions C) Persistent stimulation by motor neuron D) Decrease in the number of muscle fibers E) Increase in membrane leakiness to sodium, resulting in continuing action potentials

What term refers to the increase in the number of motor units activated as a result ofmore intensestimulation? A) Twitch B) Recruitment C) Threshold stimulation D) All-or-none response E) Summation

The muscles of the back that help maintain upright posture while standing still are undergoing what type of contractions? A) Isotonic contractions B) Isometric contractions

Activities such as distance swimming and distance running are most likely to stimulate the development of what type of muscle fiber? A) Slow fibers B) Fast fibers

What happens to a muscle that has lost its innervation? A) It undergoes hypertrophy. B) It stimulates the formation of new motor neurons. C) It undergoes atrophy. D) The muscle fibers enlarge in order to still undergo contraction.

Which statement describes multiunit smooth muscle? A) Composed of sheets of muscle cells B) Displays rhythmicity C) Found within the walls of the stomach and intestines D) Responds to stimulation by neurons and certain hormones

Compared to skeletal muscle, smooth muscle contracts __________ and relaxes __________. A) more slowly; more slowly B) more slowly; more rapidly C) more rapidly; more slowly D) more rapidly; more rapidly

What term refers to the attachment point for the movable end of the muscle? A) Origin B) Fulcrum C) Insertion D) Motor end plate E) Source

What term describes the muscle that is primarily responsible for opposing a particular action? A) Antagonist B) Prime mover C) Synergist D) Agonist

In muscle anatomy, what is an origin? A) The less movable end of a muscle B) The more movable end of the muscle C) The point of attachment of a tendon to a muscle D) The location of a neuromuscular junction E) The boundary between neighboring sarcomeres

A(n) __________ is a bundle of dense connective tissue that connects a skeletal muscle to a bone. A) origin B) insertion C) tendon D) ligament E) epimysium

Where would an antagonist to the sternocleidomastoidmuscles be located? A) On the posterior side of the body B) On the anterior side of the body C) Inferior to the clavicle

What statement describes the zygomaticusmuscle? A) It inserts on the coronoidprocess of the mandible. B) It elevates the corner of the mouth. C) It brings the head into an upright position. D) It closes the lips.

What is an action of the rectus femoris muscle? A) Extends leg at knee B) Plantar flexes the foot C) Extends the thigh at the hip D) Adducts the thigh

Layers of dense connective tissue called __________ separate and support individual muscles. A) fascia B) tendons C) cartilage D) aponeuroses

What are fascicles? A) Bundles of muscle fibers B) Bundles of collagen fibers C) Bundles of myofibrils D) Bundles of thick and thin filaments E) Bundles of smooth muscle cells

What is an alternate name for a skeletal muscle cell? A) Myofibril B) Myofilament C) Myosin D) Muscle fiber

In skeletal muscle, the thick filaments are mainly composed of ___________. A) myosin B) actin C) myofibrils D) sarcoplasm E) Z lines

What structures consist of actin and myosin filaments? A) Myofibrils B) T tubules C) Aponeuroses D) Fascicles E) Thick filaments

Skeletal muscle cells appear striated because of the presence of what parallel bundles? A) Sarcomeres B) Z lines C) Myosin D) Myofibrils E) Transverse tubules

What is the main component of thin filaments? A) Myofibrils B) Acetylcholine C) Actin D) Myosin E) Collagen

What structure within a skeletal muscle cell extends from Z line to Z line? A) Sarcolemma B) Sarcomere C) Sarcoplasmic reticulum D) A band E) I band

Name the membranouschannels or tunnels that extend inward from A) Sarcomeres B) Myofibrils C) Transverse tubules D) Cisternae E) Motor end plates

Enlarged portions of the sarcoplasmic reticulum are called __________. A) synaptic clefts B) cisternae C) H zones D) T tubules E) motor end plates

What type of neurons function to control effectors? A) Aerobic neurons B) Sensory neurons C) Axon terminals D) Motor neurons E) Motor units

What is the name of the functional connection between a motor neuron and a muscle cell? A) Motor end plate B) Synaptic cleft C) Synaptic vesicle D) Junctional plate E) Neuromuscular junction

The __________ is the gap that separates a muscle cell membrane from the neuron cell membrane in a neuromuscular junction. A) synaptic cleft B) T tubule C) motor end plate D) synaptic vesicle E) sarcoplasm

Following stenuous exercise, levels of ATP, creatine phosphate, oxygen, and glucose must be returned to normal levels. This situation, called __________, may take several hours to complete. A) oxygen debt B) muscle atrophy C) aerobic respiration D) tetany

Motor neurons communicate with muscle cells by releasing chemicals called ____________. A) neurotransmitters B) proteins C) myosin D) troponin E) tropomyosin

What is a description of the region known as the motor end plate? A) It has many openings leading into transverse tubules. B) Mitochondria are abundant. C) Synaptic vesicles are abundant. D) It functions to release neurotransmitter molecules.

What enzyme catalyzes the breakdown of the neurotransmitter used to stimulate skeletal muscle? A) Tropomyosin B) ATPase C) Acetylcholinesterase D) Norephinephrine

What neurotransmitter is used to stimulate skeletal muscle contraction? A) Norepinephrine B) Actin C) Acetylcholine D) Tropomyosin E) ATP

When acetylcholine binds to its receptors at the motor end plate, the muscle fiber membrane becomes more permeable to __________. A) potassium B) sodium C) calcium D) acetylcholine E) acetylcholinesterase

What is the effect of an increased concentration of calcium ion in the sarcoplasm? A) Actin binding sites become exposed. B) Myosin binding sites become exposed. C) Troponin binding sites become exposed. D) Actin and myosin become unable to accomplish contraction.

In skeletal muscle cells, what molecule can be used to transfer energy to ADP in order to form ATP? A) Acetylcholine B) Troponin C) Actin D) Creatinephosphate E) Glucose

In the absence of oxygen, what process is used by muscle cells to generate small amounts of ATP? A) Electron transport chain B) Glycolysis C) Aerobic respiration D) Hydrolysis of myoglobin

What is the product of the anaerobic breakdown of glucose? A) Creatine phosphate B) Pyruvic acid C) Carbon dioxide D) Water and ATP

What is the product of the aerobic breakdown of glucose? A) Creatine phosphate B) Pyruvic acid C) Lactic acid D) Carbon dioxide, water, and ATP

What molecule, only present in muscle cells, is used to temporarily store oxygen for use in aerobic respiration? A) Myoglobin B) Acetylcholine C) Creatine phosphate D) Lactic acid E) Pyruvic acid

After death, rigor mortis develops as levels of calcium in the sarcoplasm increase and levels of __________ decrease. A) ATP B) ADP C) sodium D) potassium E) myoglobin

A(n) __________ is a single contraction of a muscle fiber in response to a single stimulus. A) sustained contraction B) threshold stimulus C) twitch D) cramp E) all-or-none response

What muscle can act as a prime mover for plantar flexion of the foot? A) Gastrocnemius B) Tibialis anterior C) Extensor digitorum longus D) Biceps femoris

What results when a muscle fiber is stimulated repeatedly at a fast enough pace that, though it starts to relax between stimuli, it cannot completely relax between contractions? A) Muscle fatigue B) Complete tetaniccontraction C) Summation D) Peristalsis E) Recruitment

What is formed by a motor neuron and all the muscle cells it stimulates? A) Neuromuscular bundle B) Fascicle C) Motor unit D) Myofibril E) Motor end plate

Small, sustained contractions that are the result of repeated nervous stimulation, originating from the spinal cord and stimulating only a few muscle fibers at a time, is called __________. A) muscle tone B) tetanus C) summation D) a myogram E) a twitch

What type of muscle cell has a sarcoplasmic reticulum that is not well developed? A) Cardiac muscle cell B) Skeletal muscle cell C) Smooth muscle cell

What type of smooth muscle consists of muscle fibers that are separate rather than organized into sheets? A) Multiunit smooth muscle B) Visceral smooth muscle C) Skeletal muscle D) Cardiac muscle

What is peristalsis? A) A single contraction in response to a single stimulus of a muscle fiber B) A sustained contraction of a muscle fiber C) Wavelike smooth muscle contraction D) Contraction of progressively more motor units as stimulation strength increases E) The smallest strength of stimulus that will trigger a contraction of skeletal muscle fibers

What type of smooth muscle is found in the wall of the stomach? A) Striated muscle B) Visceral muscle C) Multiunit muscle D) Intercalated muscle

Consider the components of the lever that causes the flexion of the upper limb at the elbow. The fulcrum of the lever is the __________ and the force to move the rigid bar (the forearm bones) is provided by contraction of the __________. A) elbow joint; biceps brachii B) shoulder joint; triceps brachii C) elbow joint; triceps brachii D) shoulder joint; biceps brachii

For the biceps brachii, triceps brachii, and the quadriceps femoris, what is referred to by the prefixes "bi-", "tri-", and "quad-"? A) The number of heads (origins) B) The number of bones that are moved when the muscle contracts C) The number of insertions D) The number of aponeuroses bundling the muscles together

Using the muscle name as a clue, where is the tibialis posterior muscle located? A) At the buttocks B) At the back of the calf C) At the back of the arm D) Over the top of the foot E) Deep to the shoulder blade

Curare is a poison that binds to acetycholine receptors at the motor end plate. What is the result of curare poisoning? A) Increased acetylcholine production B) Lack of neurotransmitter release by the motor neuron C) Inability of the muscle fiber to respond to nervous stimulation D) Rapid breakdown of acetylcholine by acetylcholinesterase

The connective tissue covering that separates a muscle into fascicles is called the __________. A) perimysium B) endomysium C) epimysium

What is the effect of ATP binding to myosin? A) Cross-bridges form B) Cross-bridges break C) Troponin and tropomyosin interact to expose binding sites on actin D) Thin filaments become shorter, causing shortening of the sarcomere

In skeletal muscle fibers, what is the source of the calcium ions that are released into the sarcoplasm to bind with troponin, resulting in contraction? A) Extracellular fluid B) Sarcoplasmic reticulum C) Mitochondria D) Golgi apparatus

What type of muscle fiber is large in diameter and contains abundant glycogen and relatively few mitochondria? A) Fast fibers B) Slow fibers

With training, what changes will occur in the muscles of the lower limbs of a marathon runner? A) Development of more extensive capillary networks; cells develop more mitochondria B) Formation of more actin and myosin, causing enlargement of muscle fibers C) Loss of myoglobin and reduction in size of muscle fibers D) Drastic increase in number of muscle fibers

What type of muscle fiber will be more resistant to fatigue? A) Fast fiber B) Slow fiber

What is muscle atrophy? A) Decrease in size and strength B) Increase in number of muscle fibers C) Increase in size of muscle fibers D) Decrease in length of muscle fibers

As you go to lift your backpack off of the floor, there is a period of time when the muscles of your arm and back are contracting but your backpack has yet to move. The muscles are developing tension before they begin to shorten and before the bag begins to be lifted. This type of contraction is called an __________ contraction. A) isotonic B) isometric

A muscle that will adduct the thigh (moving it toward the midline of the body) will be located in what area? A) Inner thigh B) Buttocks C) Front of thigh D) Back of calf

Which two muscles share the same primary action? A) Temporalis and masseter B) Levator scapulae and pectoralis minor C) Supinator and pronator teres D) Biceps femoris and rectus femoris

Which muscles share the same primary action? A) Gluteus maximus and iliacus B) Gastrocnemius and soleus C) Zygomaticus and platysma D) Brachialis and triceps brachii

Using the muscle name as a clue, what is the action of the extensor carpi ulnaris? A) To extend the wrist B) To extend the arm at the shoulder C) To dorsiflex the foot D) To extend the leg at the knee

Consider a muscle that originates on the posterior femur and inserts on the posterior tibia. What is the action of this muscle? A) To flex the knee B) To flex the hip C) To extend the knee D) To extend the hip

Consider a muscle that originates on the anterior forearm and inserts on the palm of the hand. What is the action of this muscle? A) To flex the wrist B) To flex the elbow C) To extend the wrist D) To extend the elbow

Myasthenia gravis is an autoimmune disease in which an individual's own immune system produces antibodies to acetylcholine receptors, blocking or destroying them. What would be a major symptom of this disease? A) Muscle weakness B) Muscle spasms or cramps C) Hypertrophy of affected muscles D) Loss of motor neuron function

During the motion that extends the upper limb at the elbow, the triceps brachii represents which part of the lever? A) Rigid bar B) Fulcrum C) Force D) Resistance E) Handle

During the motion that extends the upper limb at the elbow, the elbow joint represents which part of the lever? A) Rigid bar B) Fulcrum C) Force D) Resistance E) Handle

Which of the following is NOT a basic component of a lever? A) Rigid bar B) Fulcrum C) Force D) Handle E) Resistance

During anaerobic respiration, pyruvic acidmolecules are converted into molecules of ____________.

One factor that may contribute to the development of muscle fatigue is an accumulation of the __________ resulting from anaerobic metabolism.

The time between the stimulation of a muscle fiber and the beginning of contraction iscalled the __________ period.

The rhythmic, wavelike motion produced by visceral smooth muscle is called __________.

The enlargement of muscle fibers as a result of exercise is called _______________.

The two neurotransmitters that affect smooth muscle cells are acetylcholine and __________.

Muscles that assist a prime mover in causing a movement are called _______________.

A broad sheet of dense connective tissue that connects muscle to its origin or insertion is called a(n) ____________.

During anaerobic respiration, pyruvic acidmolecules are converted into molecules of ____________.

One factor that may contribute to the development of muscle fatigue is an accumulation of the __________ resulting from anaerobic metabolism.

The time between the stimulation of a muscle fiber and the beginning of contraction iscalled the __________ period.

The rhythmic, wavelike motion produced by visceral smooth muscle is called __________.

The enlargement of muscle fibers as a result of exercise is called _______________.

The two neurotransmitters that affect smooth muscle cells are acetylcholine and __________.

Muscles that assist a prime mover in causing a movement are called _______________.