Chapter 10 A&P

The following is a list of the events that occur during a muscle contraction. What is the correct sequence of these events? 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. 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

3, 5, 1, 4, 6, 2

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

6, 2, 4, 5, 1, 3

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

95

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.

A band.

In rigor mortis A) the myosin heads are attached to actin. B) ATP is depleted. C) calcium ions keep binding to troponin. D) sustained contractions occur. E) All of the answers are correct

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

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

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.

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.

All of the answers are correct.

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.

I band.

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 muscles to stay contracted. D) It would cause muscles to stay relaxed. E) It would have little effect on skeletal muscles.

It would cause muscles to stay contracted.

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

M line.

The skeletal muscle complex known as the triad consists of A) actin, myosin, and titin 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.

a transverse tubule and two terminal cisternae.

Triggering of the muscle action potential occurs after A) acetylcholine binds to chemically- gated channels in the motor end plate. B) acetylcholinesterase is released from synaptic vesicles into the synaptic cleft. C) calcium ion binds to channels on the motor end plate. D) the action potential jumps across the neuromuscular junction. E) Any of these can produce an action potential in the muscle cell

acetylcholine binds to chemically-gated channels in the motor end plate.

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.

acetylcholine.

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.

active transport of calcium into the sarcoplasmic reticulum.

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.

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 ATP anaerobically. B)creatine phosphate stimulates mitochondrial activity. C) additional oxygen is required to restore energy reserves. D) the liver requires more oxygen to produce lactic acid. E) the muscles produce much less ATP.

additional oxygen is required to restore energy reserves.

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.

aerobic metabolism of fatty acids.

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

an oxygen debt

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.

calcium binds to troponin.

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.

calcium ions.

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

complete tetanus.

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

contraction.

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.

endomysium.

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

epimysium.

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.

fast fibers.

A fascicle is a A) group of muscle fibers that are encased in the perimysium. B) layer of connective tissue that separates muscle from skin. C) group of muscle fibers that are all part of the same motor unit. D) group of muscle fibers and motor neurons. E) collection of myofibrils in a muscle fiber.

group of muscle fibers that are encased in the perimysium.

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 quick twitches

have low resistance to fatigue and quick twitches

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.

have many nuclei.

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

incomplete tetanus.

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(n) ________ contraction. A) isometric B) tetanus C) isotonic D) treppe E) concentric

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.

isometric.

Because skeletal muscle contractions demand large quantities of ATP, skeletal muscles have A) a rich nerve supply to ensure a rapid succession of action potentials. B) massive creatine phosphate reserves for long periods of sustained contractions. C) extra calcium reserves which can serve as fuel molecules during ATP synthesis. D) adipose tissue between fibers to supply nutrients for ATP production. E) many mitochondria and a rich blood supply.

many mitochondria and a rich blood supply.

When acetylcholine binds to receptors at the motor end plate, the sarcolemma 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. E) less permeable to potassium and sodium ions

more permeable to sodium ions.

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.

most of the muscle's energy is produced in mitochondria.

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

motor end plate.

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

motor unit.

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.

muscle contraction.

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

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

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.

neuromuscular junction.

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.

plasticity.

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

produce large amounts of muscle proteins.

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

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.

recruitment.

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

reduces the muscle's ability for contraction

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.

repeated, exhaustive stimulation.

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

sarcolemma.

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

sarcomere.

As 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.

shortens.

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

slow

Which of the following types 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

slow fibers

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

storage and release site for calcium ions

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.

synaptic cleft.

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

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.

tendon.

The contraction of a muscle exerts a pull on a bone because muscles attach to bones by A) ligaments. B) bursae. C) tendons. D) fasciae. E) myofibrils.

tendons.

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

testosterone

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

thin filaments and thick filaments

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.

transverse tubules.

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.

tropomyosin molecules.

When calcium ion binds to troponin, A) tropomyosin rolls away from the active site. B) active sites on the myosin are exposed. C) actin heads will bind to myosin. D) muscle relaxation occurs. E) myosin shortens.

tropomyosin rolls away from the active site.

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

twitch.

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.

two actin protein strands coiled helically around each other.

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

wave summation.

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

zone of overlap.

When a skeletal muscle fiber contract the A) H bands and I bands get larger. B) zones of overlap get larger. C) Z lines move further apart. D) width of the A band increases. E) All of the answers are correct.

zones of overlap get larger.