AP 1: Chapter 11 Muscle Tissue

C) muscles that control the eyes

) In which of the following would the motor units have the fewest muscle fibers? A) muscles of the neck B) postural muscles of the back C) muscles that control the eyes D) thigh muscles E) calf muscles

A) incomplete tetanus.

A muscle producing tension that peaks and falls at intermediate stimulus rates is said to be in A) incomplete tetanus. B) complete tetanus. C) treppe. D) wave summation. E) recruitment.

E) reduces the muscle's ability for contraction

A patient takes a medication that blocks ACh receptors of skeletal muscle fibers. What is this drug's effect on skeletal muscle contraction? A) increases tone in the muscle B) causes a strong contraction similar to a "charlie horse" cramp C) increases the muscle's excitability D) produces a strong, continuous state of contraction E) reduces the muscle's ability for contraction

C) aerobic metabolism of fatty acids.

A resting muscle generates most of its ATP by A) hydrolysis of creatine phosphate. B) anaerobic respiration. C) aerobic metabolism of fatty acids. D) glycogenolysis. E) the tricarboxylic acid cycle.

C) a motor unit.

A single motor neuron together with all the muscle fibers it innervates is called A) an end foot. B) an end plate. C) a motor unit. D) a dermatome. E) a myotome.

A) isometric

A weight-lifter strains to lift a heavy weight and there is no movement of the person's arms holding on to the weight. This type of contraction is called a/an ________ contraction. A) isometric B) tetanus C) isotonic D) treppe E) concentric

C) calcium binds to troponin

Active sites on the actin become available for binding after A) actin binds to troponin. B) troponin binds to tropomyosin. C) calcium binds to troponin. D) calcium binds to tropomyosin. E) myosin binds to troponin.

D) 95

Aerobic metabolism normally provides ________ percent of the ATP demands of a resting muscle cell. A) 25 B) 50 C) 70 D) 95 E) 100

D) rigor mortis

After death, muscle fibers run out of ATP and calcium begins to leak from the sarcoplasmic reticulum into the sarcoplasm. This results in a condition known as A) tetany. B) treppe. C) depolarization. D) rigor mortis. E) oxygen debt.

A) an oxygen debt

After heavy exercise, if energy reserves in a muscle are depleted, ________ occurs. A) an oxygen debt B) paralysis C) treppe D) tetanus E) atrophy

A) tendon

At each end of the muscle, the collagen fibers of the epimysium, and each perimysium and endomysium, come together to form a A) tendon. B) satellite cell. C) ligament. D) tenosynovium. E) sheath.

D) only about one-third of the energy required by the muscle.

At peak levels of muscle exertion the mitochondria can supply A) all of the energy required by the muscle. B) 80 percent of the energy required by the muscle. C) more than half of the energy required by the muscle. D) only about one-third of the energy required by the muscle. E) only about 10 percent of the energy required by the muscle.

C) tropomyosin molecules

At rest, active sites on the actin are blocked by A) myosin molecules. B) troponin molecules. C) tropomyosin molecules. D) calcium ions. E) ATP molecules.

C) troponin molecules.

At rest, the tropomyosin molecule is held in place by A) actin molecules. B) myosin molecules. C) troponin molecules. D) ATP molecules. E) calcium ions.

E) many mitochondria and a rich blood supply.

Because skeletal muscle contractions demand large quantities of ATP, skeletal muscles have A) a rich nerve supply. B) a rich blood supply and few mitochondria C) abundant mitochondria and a poor blood supply. D) adipose tissue between fibers to supply nutrients for ATP production. E) many mitochondria and a rich blood supply.

C) acts as an energy reserve in muscle tissue.

Creatine phosphate A) is produced by the process of anaerobic respiration. B) can replace ATP in binding to myosin molecules during contraction. C) acts as an energy reserve in muscle tissue. D) is only formed during strenuous exercise. E) cannot transfer its phosphate group to ADP.

B) myosin molecules.

Cross-bridges are portions of A) actin molecules. B) myosin molecules. C) troponin molecules. D) tropomyosin molecules. E) calcium ions.

C) an increase in intracellular glycogen.

Decreased blood flow to a muscle could result in all of the following, except A) muscle fatigue. B) an oxygen debt. C) an increase in intracellular glycogen. D) a shift to anaerobic glycolysis. E) an increase in intracellular lactic acid.

C) most of the muscle's energy is produced in mitochondria

During activities requiring aerobic endurance A) glycogen and glycolysis are the primary sources of reserve energy. B) oxygen debts are common. C) most of the muscle's energy is produced in mitochondria. D) fatigue occurs in a few minutes. E) oxygen is not required.

E) All of the answers are correct.

During anaerobic glycolysis A) ATP is produced. B) pyruvic acid is produced. C) oxygen is not consumed. D) carbohydrate is metabolized. E) All of the answers are correct.

C) glucose is produced from lactic acid

During the Cori cycle, in the liver A) glucose is released from glycogen. B) lactic acid is produced from glucose. C) glucose is produced from lactic acid. D) lactic acid is produced from pyruvic acid. E) lactic acid is shuffled to muscle cells.

C) muscle fibers are unable to contract.

During the recovery period following exercise, all of the following are true, except A) lactic acid is removed from muscle cells. B) the muscle actively produces ATP. C) muscle fibers are unable to contract. D) oxygen is consumed at above the resting rate. E) heat is generated.

C) additional oxygen is required to restore energy reserves consumed during exercise.

During the recovery period the body's need for oxygen is increased because A) muscle cells are producing energy anaerobically. B) the individual is panting. C) additional oxygen is required to restore energy reserves consumed during exercise. D) the liver requires more oxygen to produce lactic acid. E) the muscles are not producing ATP.

Each skeletal muscle fiber contains ________ myofibrils. A) 50 to 100 B) 100 to 150 C) 150 to 200 D) 200 to 500 E) hundreds to thousands

Each skeletal muscle fiber contains ________ myofibrils. A) 50 to 100 B) 100 to 150 C) 150 to 200 D) 200 to 500 E) hundreds to thousands

C) neuromuscular junction

Each skeletal muscle fiber is controlled by a motor neuron at a single A) synaptic knob. B) sarcomere. C) neuromuscular junction. D) synaptic cleft. E) transverse tubule.

A) two actin protein strands coiled helically around each other.

Each thin filament consists of A) two actin protein strands coiled helically around each other. B) chains of myosin molecules. C) six molecules coiled into a helical structure. D) a rod-shaped structure with "heads" projecting from each end. E) a double strand of myosin molecules.

E) have low resistance to fatigue and have quick twitches.

Fast fibers A) have low resistance to fatigue. B) rely on aerobic metabolism. C) have many mitochondria. D) have twitches with a very brief contraction phase. E) have low resistance to fatigue and have quick twitches.

A) repeated, exhaustive stimulation.

Fast muscle fibers can adapt to aerobic metabolism by generating more mitochondria in response to A) repeated, exhaustive stimulation. B) sustained low levels of muscle activity. C) high amounts of oxygen. D) increased levels of testosterone. E) prolonged periods of inactivity.

A) integumentary

Heat energy produced from muscle contraction is released by the ________ system. A) integumentary B) respiratory C) cardiovascular D) urinary E) endocrine

C) It would stimulate energy use and heat production.

How would an elevated level of thyroid hormone in the body affect skeletal muscles? A) It would stimulate atrophy. B) It would stimulate hypertrophy. C) It would stimulate energy use and heat production. D) It would decrease heat production by muscle tissue. E) It would cause an increase in muscle mass.

C) It would cause spastic paralysis (muscles are contracted and unable to relax).

How would the loss of acetylcholinesterase from the motor end plate affect skeletal muscle? A) It would make the muscles less excitable. B) It would produce muscle weakness. C) It would cause spastic paralysis (muscles are contracted and unable to relax). D) It would cause flaccid paralysis (muscles are relaxed and unable to contract). E) It would have little effect on skeletal muscles.

D) wave summation.

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful contraction occurs. This is called A) incomplete tetanus. B) complete tetanus. C) treppe. D) wave summation. E) recruitment.

A) zone of overlap.

In a sarcomere, cross-bridge attachment occurs specifically in the A) zone of overlap. B) A band. C) I band. D) M line. E) H band.

B) M line.

In a sarcomere, thick filaments are linked laterally by proteins of the A) Z line. B) M line. C) H band. D) A band. E) I band.

A) muscle tension exceeds the load and the muscle lifts the load.

In an isotonic contraction, A) muscle tension exceeds the load and the muscle lifts the load. B) tension rises and falls but the muscle length is constant. C) the peak tension is less than the load. D) many twitches always fuse into one. E) postural muscles stabilize the vertebrae.

D) calcium ions.

In response to action potentials arriving along the transverse tubules, the sarcoplasmic reticulum releases A) acetylcholine. B) sodium ions. C) potassium ions. D) calcium ions. E) hydrogen ions.

E) All of the answers are correc

In rigor mortis A) the myosin heads are attached to actin. B) ATP is depleted. C) muscles are inextensible. D) cross-bridge cycling is absent. E) All of the answers are correc

C) muscle contraction

Interactions between actin and myosin filaments of the sarcomere are responsible for A) muscle fatigue. B) the conduction of neural stimulation to the muscle fiber. C) muscle contraction. D) muscle relaxation. E) the striped appearance of skeletal muscle.

C) fast fibers.

Large-diameter, densely packed myofibrils, large glycogen reserves, and few mitochondria are characteristics of A) slow fibers. B) intermediate fibers. C) fast fibers. D) red muscles. E) fatty muscles.

B) have many nuclei.

Muscle fibers differ from "typical cells" in that muscle fibers A) lack a plasma membrane. B) have many nuclei. C) are very small. D) lack mitochondria. E) have large gaps in the cell membrane.

B) contraction.

Muscle tissue, one of the four basic tissue groups, consists chiefly of cells that are highly specialized for A) conduction. B) contraction. C) peristalsis. D) cushioning. E) secretion.

A) fast fibers.

Muscles that move the eyeball have A) fast fibers. B) slow fibers. C) intermediate fibers. D) circular fibers. E) All of the answers are correct.

E) All of the answers are correct.

Muscular force can be adjusted to match different loads by A) varying the frequency of action potentials in motor neurons. B) recruiting larger motor units. C) recruiting more motor units. D) involving more muscle fibers in the contraction. E) All of the answers are correct.

A) endomysium.

Nerves and blood vessels that service a muscle fiber are located in the connective tissues of its A) endomysium. B) perimysium. C) sarcolemma. D) sarcomere. E) myofibrils.

B) decreased width of the H band during contraction.

Physical evidence that supports the sliding filament theory of muscle contraction includes A) constant distance between Z lines during contraction. B) decreased width of the H band during contraction. C) increased width of the I band during contraction. D) decreased width of the A band during contraction. E) the I band + H band distance is constant during contraction.

C) 6, 2, 4, 5, 1, 3

Put the following structures in order from superficial to deep: 1. muscle fiber 2. perimysium 3. myofibril 4. fascicle 5. endomysium 6. epimysium A) 1, 5, 4, 3, 2, 6 B) 6, 2, 5, 4, 1, 3 C) 6, 2, 4, 5, 1, 3 D) 1, 3, 5, 6, 4, 2 E) 2, 3, 1, 4, 6, 5

B) motor end plate.

Receptors for acetylcholine are located on the A) synaptic knob. B) motor end plate. C) sarcomere. D) synaptic cleft. E) transverse tubule.

B) shortens.

Since each myofibril is attached at either end of the muscle fiber, when sarcomeres shorten, the muscle fiber A) lengthens. B) shortens. C) strengthens. D) weakens. E) pulls from the middle.

C) myoblasts

Skeletal muscle fibers are formed from embryonic cells called A) sarcomeres. B) myofibrils. C) myoblasts. D) fascicles. E) myomeres

D) recruitment

Suppose that you try to pick up an object and discover that it is much heavier than you expected. Which process must occur in the muscle to increase tension so you can pick up the object? A) wave summation B) isotonic contraction C) complete tetanus D) recruitment E) treppe

D) plasticity.

The ability of smooth muscle to function over a wide range of lengths is called A) elasticity. B) contractility. C) extensibility. D) plasticity. E) variability.

C) transverse tubules

The action potential is conducted into a skeletal muscle fiber by A) motor end plates. B) neuromuscular junctions. C) transverse tubules. D) triads. E) sarcoplasmic reticulum.

D) the ability to produce large amounts of the muscle proteins needed for growth and repair.

The advantage of having many nuclei in a skeletal muscle fiber is A) the ability to contract. B) the ability to produce more ATP with little oxygen. C) the ability to store extra DNA for metabolism. D) the ability to produce large amounts of the muscle proteins needed for growth and repair. E) the ability to produce nutrients for muscle contraction.

C) H band

The area in the center of the A band that contains no thin filaments is the A) Z line. B) M line. C) H band. D) I band. E) zone of overlap.

B) tendon

The bundle of collagen fibers at the end of a skeletal muscle that attaches the muscle to bone is called a(n) A) fascicle. B) tendon. C) ligament. D) epimysium. E) myofibril.

C) muscles are attached to bones by tendons.

The contraction of a muscle exerts a pull on a bone because A) muscles are attached to bones by ligaments. B) muscles are attached to bones by bursae. C) muscles are attached to bones by tendons. D) muscle fibers directly attach to the periosteum of bone. E) muscles elongate upon contraction.

C) acetylcholine.

The cytoplasm of the neuromuscular terminal contains vesicles filled with molecules of the neurotransmitter A) epinephrine. B) norepinephrine. C) acetylcholine. D) antidiuretic hormone. E) adrenaline.

A) endomysium

The delicate connective tissue that surrounds the skeletal muscle fibers and ties adjacent muscle fibers together is the A) endomysium. B) perimysium. C) epimysium. D) superficial fascia. E) periosteum.

B) epimysium

The dense layer of connective tissue that surrounds an entire skeletal muscle is the A) tendon. B) epimysium. C) endomysium. D) perimysium. E) fascicle.

D) 3, 5, 1, 4, 6, 2

The following is a list of the events that occur during a muscle contraction. 1. Myosin cross-bridges bind to the actin. 2. The free myosin head splits ATP. 3. Calcium ion is released from the sarcoplasmic reticulum. 4. The myosin head pivots toward the center of the sarcomere. 5. Calcium ion binds to troponin. 6. The myosin head binds an ATP molecule and detaches from the actin. The correct sequence of these events is A) 1, 3, 5, 4, 6, 2. B) 5, 1, 4, 6, 2, 3. C) 3, 5, 1, 2, 4, 6. D) 3, 5, 1, 4, 6, 2. E) 1, 4, 6, 2, 3, 5

E) recruitment.

The increase in muscle tension that is produced by increasing the number of active motor units is called A) incomplete tetanus. B) complete tetanus. C) treppe. D) wave summation. E) recruitment.

B) active transport of calcium into the sarcoplasmic reticulum.

The most important factor in decreasing the intracellular concentration of calcium ion after contraction is A) active transport of calcium across the sarcolemma. B) active transport of calcium into the sarcoplasmic reticulum. C) active transport of calcium into the synaptic cleft. D) diffusion of calcium out of the cell. E) diffusion of calcium into the sarcoplasmic reticulum.

B) loss of acetylcholine receptors in the end-plate membrane.

The muscle weakness of myasthenia gravis results from A) insufficient acetylcholine release from presynaptic vesicles. B) loss of acetylcholine receptors in the end-plate membrane. C) the motor neuron action potential being too small to shock the muscle fibers. D) excessive acetylcholinesterase that destroys the neurotransmitter. E) inability of the muscle fiber to produce ATP.

D) synaptic cleft.

The narrow space between the synaptic terminal and the muscle fiber is the A) synaptic knob. B) motor end plate. C) motor unit. D) synaptic cleft. E) M line.

A) sarcolemma.

The plasma membrane of a skeletal muscle fiber is called the A) sarcolemma. B) sarcomere. C) sarcosome. D) sarcoplasmic reticulum. E) sarcoplasm.

C) a twitch.

The rapid rise and fall in force produced by a muscle fiber after a single action potential is A) a tetanus. B) an unfused tetanus. C) a twitch. D) an end plate potential. E) a muscle action potential.

D) A band.

The region of the sarcomere containing the thick filaments is the A) Z line. B) M line. C) H band. D) A band. E) I band.

E) I band.

The region of the sarcomere that always contains thin filaments is the A) Z line. B) M line. C) H band. D) A band. E) I band.

B) sarcomere.

The repeating unit of a skeletal muscle fiber is the A) sarcolemma. B) sarcomere. C) sarcoplasmic reticulum. D) myofibril. E) myofilament.

A) sarcoplasmic reticulum.

The series of membranous channels that surround each myofibril is the A) sarcoplasmic reticulum. B) sarcoplasm. C) sarcomere. D) sarcolemma. E) endomysium

B) a transverse tubule and two terminal cisternae.

The skeletal muscle complex known as the triad consists of A) actin, myosin, and filaments. B) a transverse tubule and two terminal cisternae. C) filaments, myofibrils, and sarcomeres. D) A bands, H bands, and I bands. E) actin, myosin, and sarcomeres.

E) All of the answers are correct.

The thin filaments of striated muscle are made primarily of which protein(s)? A) actin B) tropomyosin C) troponin D) nebulin E) All of the answers are correct.

E) isometric.

The type of contraction in which the muscle fibers do not shorten is called A) tetany. B) treppe. C) concentric. D) isotonic. E) isometric.

B) slow

The type of muscle fiber that is most resistant to fatigue is the ________ fiber. A) fast B) slow C) intermediate D) anaerobic E) high-density

A) acetylcholine binds to chemically-gated channels in the end plate membrane.

Triggering of the muscle action potential occurs after A) acetylcholine binds to chemically-gated channels in the end plate membrane. B) acetylcholinesterase binds to receptors on the end plate. C) calcium ion binds to channels on the end plate. D) the nerve action potential jumps across the neuromuscular junction. E) Any of the above can produce an action potential in the muscle cell.

B) complete tetanus

When a muscle is stimulated repeatedly at a high rate, the amount of tension gradually increases to a steady maximum tension. This is called A) incomplete tetanus. B) complete tetanus. C) a twitch. D) wave summation. E) recruitment.

E) All of the answers are correct.

When a skeletal muscle fiber contracts, A) the H bands and I bands get smaller. B) the zones of overlap get larger. C) the Z lines get closer together. D) the width of the A band remains constant. E) All of the answers are correct.

A) more permeable to sodium ions.

When acetylcholine binds to receptors at the motor end plate, the end plate membrane becomes A) more permeable to sodium ions. B) less permeable to sodium ions. C) more permeable to calcium ions. D) less permeable to potassium ions.

A) tropomyosin moves into the groove between the helical actin strands

When calcium ion binds to troponin, A) tropomyosin moves into the groove between the helical actin strands. B) active sites on the myosin are exposed. C) actin heads will bind to myosin. D) muscle relaxation occurs. E) myosin shortens.

E) All of the answers are correct.

When comparing slow muscle fibers to fast muscle fibers, slow fibers A) take about three times as long to reach peak tension. B) have much smaller fiber diameters. C) generate much less tension. D) are rich in the red protein myoglobin. E) All of the answers are correct.

E) All of the answers are correct.

When contraction occurs, A) the H bands get smaller. B) the Z lines move closer together. C) the width of the A band remains constant. D) the I bands get smaller. E) All of the answers are correct.

D) the head portion of the myosin molecule

Which of the following acts as an ATPase during the contraction cycle of muscle? A) actin molecules B) troponin molecules C) tropomyosin molecules D) the head portion of the myosin molecule E) the tail portion of the myosin molecule

A) thin filaments and thick filaments

Which of the following become connected by myosin cross-bridges during muscle contraction? A) thin filaments and thick filaments B) thick filaments and titin filaments C) z disks and actin filaments D) thick filaments and t-tubules E) thin filaments and t-tubules

D) thin filaments are anchored here

Which of the following best describes the term Z line? A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules

B) repeating unit of striated myofibrils

Which of the following best describes the term sarcomere? A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules

C) storage and release site for calcium ions

Which of the following best describes the term sarcoplasmic reticulum? A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage and release site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules

A) protein that accounts for elasticity of resting muscle

Which of the following best describes the term titin? A) protein that accounts for elasticity of resting muscle B) repeating unit of striated myofibrils C) storage site for calcium ions D) thin filaments are anchored here E) largely made of myosin molecules

C) testosterone

Which of the following hormones directly stimulates growth of muscle tissue, leading to increased muscle mass? A) epinephrine B) thyroid hormone C) testosterone D) parathyroid hormone E) calcitonin

E) All of the answers are correct.

Which of the following is a recognized function of skeletal muscle? A) produce movement B) maintain posture C) maintain body temperature D) guard body entrances and exits E) All of the answers are correct.

C) forcing blood from the heart into the major arteries

Which of the following is not a function of smooth muscle tissue? A) altering the diameter of the respiratory passageways B) elevating hairs on the arm C) forcing blood from the heart into the major arteries D) moving food materials along the digestive tract E) forcing urine out of the urinary tract

A) Smooth muscle connective tissue forms tendons and aponeuroses.

Which of the following is not characteristic of smooth muscle? A) Smooth muscle connective tissue forms tendons and aponeuroses. B) Neurons that innervate smooth muscles are under involuntary control. C) Smooth muscle cells are uninucleate. D) Smooth muscles do not contain sarcomeres. E) The thin filaments of smooth muscle fibers are attached to dense bodies.

E) All of the answers are correct.

Which of the following statements is (are) true regarding human muscles? A) Most have both slow and fast fibers. B) Slow fibers are abundant in the calf muscles. C) Eye muscles are composed entirely of fast fibers. D) Slow fibers are abundant in the back muscles. E) All of the answers are correct.

D) Cardiac muscle stimulation is neural.

Which of the following statements is false? A) Cardiac muscle contractions cannot be summated. B) Skeletal muscle contractions may be summated. C) Skeletal muscle stimulation is neural. D) Cardiac muscle stimulation is neural. E) Cardiocytes are interconnected through intercalated discs.

E) All of the answers are correct.

Which of these would lead to increased oxygen consumption? A) increased heat production B) increased conversion of lactic acid to glucose C) increased aerobic respiration by muscle cells D) increased muscle activity E) All of the answers are correct.

A) Calcium ion is released from the transverse tubule.

Which statement about excitation-contraction coupling is incorrect? A) Calcium ion is released from the transverse tubule. B) Calcium ion is released from the sarcoplasmic reticulum. C) Tropomyosin moves to expose myosin binding sites on actin. D) Troponin binds calcium ion and signals tropomyosin to move. E) Relaxation requires uptake of calcium ion by the sarcoplasmic reticulum.

E) All of the answers are correct.

Which statement about the microscopic anatomy of skeletal muscle fibers is true? A) Tubular extensions of the sarcolemma penetrate the fiber transversely. B) Cross striations result from the lateral alignment of thick and thin filaments. C) Each fiber has many nuclei. D) Muscle fibers are continuous from tendon to tendon. E) All of the answers are correct.

D) slow fibers

Which type of muscle fibers are best adapted for prolonged contraction such as standing all day? A) uninucleated fibers B) striated fibers C) fast fibers D) slow fibers E) intermediate fibers