A) are under involuntary control.
B) are striated.
C) are widely distributed in the body.
D) have multiple nuclei.
E) are under voluntary control.
Correct Answer
verified
Multiple Choice
A) longer than the length of a contracted sarcomere.
B) shorter than the length of a contracted sarcomere.
C) the same length as a contracted sarcomere.
D) the same length as the muscle fiber.
E) the same length as the myofibril.
Correct Answer
verified
Multiple Choice
A) cell membrane of a muscle fiber.
B) cytoplasm of muscle cells.
C) structural and functional unit of the skeletal muscle cell.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin.
Correct Answer
verified
Multiple Choice
A) I band - contains only actin
B) M line - middle of the H zone
C) Z disk - structure between adjacent sarcomeres
D) myosin myofilaments - thin myofilaments
E) actin myofilaments - thin myofilaments
Correct Answer
verified
Multiple Choice
A) perimysium
B) endomysium
C) epimysium
D) paramysium
E) sarcolemma
Correct Answer
verified
Multiple Choice
A) increased motor unit recruitment
B) increased concentration of calcium ions around the myofibrils
C) exposure of more active sites on myosin myofilaments
D) the breakdown of elastic elements in the cell
E) decreased stimulus frequency
Correct Answer
verified
Multiple Choice
A) cell membrane of a muscle fiber.
B) cytoplasm of muscle cells.
C) structural and functional unit of the skeletal muscle cell.
D) contractile thread that extends the length of the muscle fiber.
E) protein strand composed of actin or myosin.
Correct Answer
verified
Multiple Choice
A) chronic muscle pain.
B) decreased size of muscle fibers.
C) spastic contractions of muscles.
D) replacement of muscle cells by connective tissue.
E) hypertrophy of muscle tissue.
Correct Answer
verified
Multiple Choice
A) calcium ions diffuse into the presynaptic terminal through voltage-gated ion channels.
B) acetylcholine moves into the presynaptic terminal.
C) a local potential is generated in the presynaptic terminal.
D) ligand-gated ion channels in the presynaptic terminal are opened.
E) nothing else happens.
Correct Answer
verified
Multiple Choice
A) calcium ions must be transported to troponin.
B) power strokes slow down.
C) the active sites on actin must be blocked.
D) sodium ions must be actively transported to troponin.
E) the active sites on myosin must be uncovered.
Correct Answer
verified
Multiple Choice
A) loss of muscle strength
B) loss of synapse surface area
C) loss of fast-twitch fibers
D) decreased recovery time
E) decrease in motor units
Correct Answer
verified
Multiple Choice
A) of its positive electrical charge.
B) there are more leak ion channels for K+ than Na+.
C) protein molecules cannot exit through the cell membrane.
D) calcium ions block Na+ and Cl- channels.
E) there are more gated channels for K+.
Correct Answer
verified
Multiple Choice
A) 4, 2, 3, 1
B) 2, 1, 4, 3
C) 3, 1, 4, 2
D) 2, 3, 1, 4
E) 1, 2, 3, 4
Correct Answer
verified
Multiple Choice
A) an increased number of muscle fibers.
B) the nervous system's ability to recruit a large number of motor units simultaneously.
C) elimination of unnecessary enzymes and metabolic pathways.
D) elimination of all fat deposits.
E) elimination of unnecessary connective tissue.
Correct Answer
verified
Multiple Choice
A) In isometric contractions, the amount of tension produced by the muscle is constant.
B) In isotonic contractions, the muscle fibers shorten.
C) The contractile processes in isometric and isotonic contractions are the same.
D) Most skeletal muscle contractions are a combination of isometric and isotonic contractions.
E) In isotonic contractions, the amount of tension produced by the muscle fibers is constant during the contraction.
Correct Answer
verified
Multiple Choice
A) anaerobic respiration
B) aerobic respiration
C) both anaerobic and aerobic respiration
Correct Answer
verified
Multiple Choice
A) breaks down glycogen
B) synthesizes ATP
C) acts as a reservoir for oxygen
D) produces action potentials
E) stores glucose
Correct Answer
verified
Multiple Choice
A) Skeletal muscle is capable of spontaneous contraction.
B) Smooth muscle is found in the walls of hollow organs.
C) Cardiac muscle cells have multiple nuclei.
D) Smooth muscle cells are long and cylindrical.
E) There is a small amount of smooth muscle in the heart.
Correct Answer
verified
Multiple Choice
A) skeletal muscle
B) smooth muscle
C) cardiac muscle
Correct Answer
verified
Multiple Choice
A) incomplete tetanus.
B) twitch.
C) multiple wave summation.
D) all or none response.
E) none of these.
Correct Answer
verified
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