Chapter 10 Study Guide

The advantage of having many nuclei in a skeletal muscle fiber is A) the ability to produce large amounts of the enzymes and structural proteins needed for contraction. B) the ability to repair the fiber after an injury. C) the ability to contract. D) the ability to produce more ATP with little oxygen. E) both B and C

The ability to produce large amounts of the enzymes and structural proteins needed for contraction.

Which of the following statements is incorrect? A) Skeletal muscles are responsible for controlling the openings of the digestive and urinary tracts. B) Skeletal muscle contractions help maintain body temperature. C) Skeletal muscles are responsible for the pumping action of the heart. D) Skeletal muscles support the weight of some internal organs. E) The contractions of skeletal muscles pull on tendons and move bones of the skeleton.

Skeletal muscles are responsible for the pumping action of the heart.

Thin filaments at either end of the sarcomere are attached to the A) Z line. B) M line. C) H band. D) A band. E) I band.

Z line

Which of the following muscles would contract more forcefully? A) a muscle receiving 5 action potentials per second B) a muscle receiving 10 to 15 action potentials per second

a muscle receiving 10 to 15 action potentials per second

Which of the following muscles would produce the greater tension? A) a muscle with 10 motor units active B) a muscle with 20 motor units active

a muscle with 20 motor units

Because skeletal muscle contractions demand large quantities of ATP, skeletal muscles have A) very few mitochondria. B) a rich vascular supply. C) a rich nerve supply. D) little need for oxygen. E) a large concentration of tissue hemoglobin.

a rich vascular supply

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

myosin cross-bridges

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

plasticity

Fast fibers A) produce powerful contractions. B) have high resistance to fatigue. C) have many mitochondria. D) have a low concentration of myoglobin. E) both B and D

produce power contractions

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

recruitment

Fast muscle fibers can develop a larger number of mitochondria in response to A) high amounts of oxygen. B) repeated, exhaustive stimulation. C) prolonged periods of inactivity. D) increased levels of testosterone. E) sustained low levels of muscle activity.

repeated, exhaustive stimulation

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

testosterone

Knowing the five steps that occur causing a neuron to stimulate a muscle fiber, if there is a problem with the release of calcium ions in the third step, ________. A) acetylcholine is not released. B) the action potential does not arrive. C) the action potential does not appear in the sarcolemma. D) the force does not return to the initial site. E) the acetylcholine does not bind to the motor end plate.

the action potential does not appear in the sarcolemma

Skeletal muscle contracts only under stimulation from A) the central nervous system. B) the sympathetic nervous system. C) the parasympathetic nervous system. D) all of the above E) none of the above

the central nervous system

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

endomysium

The dense layer of collagen fibers that surround an entire skeletal muscle is the A) perimysium. B) epimysium. C) fascicle. D) endomysium. E) tendon.

epimysium

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

myosin molecules

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

neuromuscular junction

At peak levels of muscle exertion the mitochondria can supply A) only about 10 percent of the energy required by the muscle. B) 80 percent of the energy required by the muscle. C) only about 1/3 of the energy required by the muscle. D) more than half of the energy required by the muscle. E) all of the energy required by the muscle.

only about 1/3 of the energy required by the muscle

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

perimysium

Each thin filament consists of A) chains of myosin molecules. B) a rod-shaped structure with "heads" projecting from each end. C) 6 molecules coiled into a helical structure. D) a pair of protein strands wound together. E) a double strand of myosin molecules.

A pair of protein strands wound together

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

A band

The pull called tension is a(n) ________ force. A) aggressive B) assertive C) active D) passive E) all of the above

active

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) 5, 1, 4, 6, 2, 3. B) 3, 5, 1, 2, 4, 6. C) 1, 4, 6, 2, 3, 5. D) 3, 5, 1, 4, 6, 2. E) 1, 3, 5, 4, 6, 2.

3, 5, 1, 2, 4, 6

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

95

Calcium ions are released from the sarcoplasmic reticulum during the ________ of contraction. A) latent period B) contraction phase C) recovery phase D) relaxation phase E) A and B

A and B latent period and relaxation phase

When contraction occurs, A) the H and I bands get smaller. B) the width of the A band remains constant. C) the Z lines move closer together. D) A, B, and C E) none of the above

A, B, and C The H and I bands get smaller.; The width of the A band remains constant.; The Z lines move closer together.

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

Cardiac muscle control is neural

The area in the center of the A band that contains only thick filaments is the A) Z line. B) M line. C) H band. D) I band. E) zone of overlap.

H band

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

I band

How would a drug that competes with acetylcholine for receptors at the motor end plate affect skeletal muscle? A) It would cause flaccid paralysis (muscles are relaxed and unable to contract). B) It would cause spastic paralysis (muscles are contracted and unable to relax). C) It would have no effect on skeletal muscles. D) It would make the muscles more excitable. E) It would produce uncontrolled muscle spasms.

It would cause flaccid paralysis (muscles are relaxed and unable to contract).

How would blocking the activity of acetylcholinesterase affect skeletal muscle? A) It would make the muscles less excitable. B) It would have no effect on skeletal muscles. C) It would cause spastic paralysis (muscles are contracted and unable to relax). D) It would produce muscle weakness. E) It would cause flaccid paralysis (muscles are relaxed and unable to contract).

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

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

M line

Which of the following statements is incorrect? A) When the muscle is fully stretched, contraction cannot occur. B) Sarcomeres can produce the most tension when stimulated over a relatively narrow range of intermediate resting lengths. C) All sarcomeres in a muscle fiber contract and relax together. D) When the sarcomeres are slightly less than fully shortened, contraction cannot occur. E) When the sarcomeres are fully shortened, contraction cannot occur.

Sarcomeres can produce the most tension when stimulated over a relatively wide range of resting lengths

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

a transverse tubule and terminal cisternae

The cytoplasm of the synaptic terminal contains mitochondria and vesicles filled with molecules of the neurotransmitter A) acetylcholine. B) epinephrine. C) antidiuretic hormone. D) norepinephrine. E) all of the above

acetylcholine

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

active transport of calcium into the sarcoplasmic reticulum

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

acts as an energy reserve in muscle tissue

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

additional oxygen is required to metabolize the lactic acid produced during exercise.

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

aerobic respiration

During anaerobic glycolysis A) ATP is produced. B) lactic acid is produced if pyruvic acid accumulates. C) pyruvic acid is produced. D) all of the above E) A and B only

all of the above ATP is produced.; lactic acid is produced if pyruvic acid accumulates.; pyruvic acid is produced.

In order for a muscle to contract properly, it requires A) oxygen. B) an adequate blood supply. C) energy. D) nutrients. E) all of the above

all of the above Oxygen; An adequate blood supply; Energy; Nutrients

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

all of the above The zones of overlap get larger.; The Z lines get closer together.; The width of the A band gets constant.; The H zones and I bands get smaller.

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

an increase in intracellular glycogen

Differences between skeletal muscle cells and typical cells include which of the following? A) Skeletal muscle cells are larger than normal cells. B) Skeletal muscle cells are multinucleate. C) Skeletal muscle cells have one nucleus and typical cells have more than one. D) both A and B E) both A and C

both A and B Skeletal muscle cells are larger than normal cells; Skeletal muscle cells are multinucleate

Which of the following statements are true regarding human muscles? A) All human muscles have both slow and fast fibers. B) Fast fibers are found in the calf muscles. C) Eye and hand muscles are composed of fast fibers. D) Back muscles are mostly composed of endurance fibers. E) both C and D

both C and D Eye and hand muscles are composed of fast fibers; Back muscles are mostly composed of endurance fibers

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

calcium binds to troponin

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

calcium ions

The sarcoplasmic reticulum stores A) ATP. B) glucose. C) oxygen. D) glycogen. E) calcium ions.

calcium ions

A muscle that is stimulated so frequently that the relaxation phase is completely eliminated is said to exhibit A) complete tetanus. B) recruitment. C) wave summation. D) treppe. E) incomplete tetanus.

complete tetanus

Muscle tissue, one of the four primary types of tissue, consists chiefly of muscle cells that are highly specialized for A) contraction. B) conduction. C) peristalsis. D) all of the above E) none of the above

contraction

Increased oxygen consumption would accompany all of the following, except A) increased heat production. B) increased aerobic respiration by muscle cells. C) increased muscle activity. D) decreased ATP use. E) increased conversion of lactate to glucose.

decreased ATP use

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

decreased distance between Z lines during contraction

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

fast fibers

When energy reserves in a muscle are exhausted and lactic acid levels increase, ________ occurs. A) an oxygen debt B) tetanus C) treppe D) atrophy E) fatigue

fatigue

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

forcing blood from the heart into the major arteries

During the Cori cycle in the liver A) glucose is produced from lactic acid. B) creatine phosphate is produced. C) glycogen is produced from glucose. D) glucose is produced from glycogen. E) lactic acid is produced from glucose.

glucose is produced from lactic acid

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

have many nuclei

During muscle contraction, all of the following occur, except A) myosin heads bind to actin. B) hemoglobin concentration in muscle fibers increases. C) the H band becomes shorter. D) ATP is hydrolyzed. E) calcium concentration in the sarcomere increases.

hemoglobin concentration in muscle fibers increases

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

hundreds to thousands

A muscle producing peak tension with rapid cycles of contraction and relaxation is said to be in A) wave summation. B) incomplete tetanus. C) treppe. D) complete tetanus. E) recruitment.

incomplete tetanus

In which of the following would the ratio of motor neurons to muscle fibers be the greatest? A) muscles that control the eye B) large muscles of the upper arms C) leg muscles D) the calf muscle E) postural muscles of the back

muscles that control the eye

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

myoblasts

Each of the following factors would increase the probability of skeletal muscles contracting, except one. Identify the exception. A) increased permeability of the muscle membrane to potassium ion B) increased numbers of acetylcholine receptors at the motor end plate C) increased amounts of acetylcholine in the synaptic cleft D) increased permeability of the muscle membrane to sodium ion E) increased permeability of the muscle membrane to calcium ions

increased permeability of the muscle membrane to potassium ion

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

integumentary

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

isometric

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

it would stimulate metabolism

Which of the following is not a function of skeletal muscle? A) maintain body temperature B) produce movement C) maintain posture D) none of the above E) B and C only

maintain body temperature

The bacterium that causes tetanus produces a toxin that affects the central nervous system and skeletal muscles, producing powerful tetanic contractions of the skeletal muscles. The toxin probably acts by A) making the cell membranes more permeable to calcium ion. B) increasing the amount of potassium ion in the intercellular fluid. C) making the cells less permeable to sodium ions. D) competing with acetylcholine for receptors at the motor end plate. E) increasing the amount of acetylcholinesterase in the synapse.

making the cell membranes more permeable to calcium ion

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

more permeable to sodium ions

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

most of the muscle's energy is produced in mitochondria

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

motor end plate

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

muscle contraction

Each of the following changes in the skeletal muscles is a consequence of aging except that A) muscle fibers become smaller in diameter. B) muscles fatigue more rapidly. C) muscles become less elastic. D) muscle fibers increase their reserves of glycogen. E) there is a steady decrease in the number of satellite cells.

muscle fibers increase their reserves of glycogen

During the recovery period following exercise, all of the following are true, except A) oxygen is consumed. B) heat is generated. C) muscle fibers remain contracted. D) lactic acid is removed from muscle cells. E) the muscle actively produces ATP.

muscle fibers remain contracted

The contraction of a muscle exerts a pull on a bone because A) muscles are directly attached to bones. B) muscles are attached to bones by tendons. C) muscles are attached to bones by ligaments. D) A, B, and C E) none of the above

muscles are attached to bones by tendons

Contractions that utilize anaerobic ATP production A) rely on slow muscle fibers. B) do not require myoglobin. C) do not rely on the energy reserves of creatine phosphate. D) require maximal contraction of muscles for short periods of time. E) do not use ATP very quickly.

require maximal contraction of muscles for short periods of time

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) depolarization. B) oxygen debt. C) rigor mortis. D) tetany. E) treppe.

rigor mortis

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

sarcolemma

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

sarcomere

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

sarcoplasm

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

sarcoplasmic reticulum

Knowing that the myofibrils are attached at the Z line of the sarcolemma and at either end of the muscle fiber, when myofibrils get shorter, the muscle fiber A) shortens. B) strengthens. C) lengthens. D) weakens. E) none of the above

shortens

If a person was suffering from severe hyperkalemia, you would expect A) skeletal muscles to be unresponsive and the heart muscle would undergo cardiac arrest. B) the potassium ion concentration of the interstitial fluid to be less than normal. C) muscle weakness and increased strength of twitch contractions. D) the membrane potential of nerves and muscles to be more negative. E) both A and D

skeletal muscles to be unresponsive and the heart muscle would undergo cardiac arrest.

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

slow

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

smooth muscle connective tissue forms tendons and aponeuroses

The types of muscle tissue include all of the following except A) striated muscle. B) cardiac muscle. C) skeletal muscle. D) smooth muscle. E) none of the above

striated muscle

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

synaptic cleft

At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium come together to form either a bundle known as a ________, or a broad sheet called an aponeurosis. A) tendon B) satellite cells C) fascicle D) joint E) none of the above

tendon

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

tendon

In an isotonic contraction, A) tension rises and the skeletal muscle length changes. B) the peak tension developed is less than the resistance. C) the muscle as a whole does not change length. D) muscle tension exceeds the resistance and the muscle shortens. E) all of the above

tension rises and the skeletal muscle length changes

Which of the following is greater? A) the concentration of calcium ion in the sarcoplasmic reticulum of a resting muscle B) the concentration of calcium ion in the sarcoplasm of a resting muscle

the concentration of calcium ion in the sarcoplasmic reticulum of a resting muscle

When myosin cross-bridges bind to the active sites on actin, A) the I band moves closer to the Z line. B) they pivot toward the M line. C) ATP is hydrolyzed. D) the sarcomere strengthens. E) muscle relaxation occurs.

they pivot toward the M line

Action potentials are conducted into a skeletal muscle fiber by A) neuromuscular junctions. B) transverse tubules. C) sarcoplasmic reticulum. D) motor end plates. E) triads.

transverse tubules

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

tropomyosin molecules

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

tropomyosin moves out of the groove between the actin molecules

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

troponin molecules

The type of contraction represented by a single stimulus/contraction/relaxation sequence is a(n) A) summation. B) incomplete tetanus. C) twitch. D) incomplete summation. E) complete tetanus.

twitch

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

wave summation

When a muscle is stimulated repeatedly for several seconds with a constant stimulus, the amount of tension gradually increases to a maximum. This phenomenon is called A) incomplete tetanus. B) a twitch. C) complete tetanus. D) wave summation. E) recruitment.

wave summation