A&P ch10p1

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) joint D) fascicle E) none of the above

A

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

A

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

A

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.

A

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.

A

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

A

muscle fiber A) surrounded by endomysium and contains myofibrils B) surrounded by sarcoplasmic reticulum and consists of sarcomeres C) surrounded by epimysium and contains muscle fascicles D) surrounded by perimysium and contains muscle fibers E) contains thick and thin filaments

A

A single thin filament contains one protein. A) True B) False

B

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.

B

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

B

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

B

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

B

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

B

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

B

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.

B

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

B

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

B

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

B

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

B

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

B

myofibril A) surrounded by endomysium and contains myofibrils B) surrounded by sarcoplasmic reticulum and consists of sarcomeres C) surrounded by epimysium and contains muscle fascicles D) surrounded by perimysium and contains muscle fibers E) contains thick and thin filaments

B

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

C

Active sites on the actin become available for binding when 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.

C

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

C

How would blocking the activity of acetylcholinesterase 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 no effect on skeletal muscles.

C

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

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

C

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

C

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

C

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 uses 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 and exposes the active site. 6. The myosin head 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.

C

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

C

skeletal muscle A) surrounded by endomysium and contains myofibrils B) surrounded by sarcoplasmic reticulum and consists of sarcomeres C) surrounded by epimysium and contains muscle fascicles D) surrounded by perimysium and contains muscle fibers E) contains thick and thin filaments

C

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

D

How would a drug that competes with acetylcholine for receptors at the motor end plate affect skeletal muscle? A) It would make the muscles more excitable. B) It would produce uncontrolled muscle spasms. 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 no effect on skeletal muscles.

D

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

D

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

D

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

D

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

D

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

D

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

D

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

D

muscle fascicle A) surrounded by endomysium and contains myofibrils B) surrounded by sarcoplasmic reticulum and consists of sarcomeres C) surrounded by epimysium and contains muscle fascicles D) surrounded by perimysium and contains muscle fibers E) contains thick and thin filaments

D

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.

E

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

E

sarcomere A) surrounded by endomysium and contains myofibrils B) surrounded by sarcoplasmic reticulum and consists of sarcomeres C) surrounded by epimysium and contains muscle fascicles D) surrounded by perimysium and contains muscle fibers E) contains thick and thin filaments

E