1) Which of the following is a recognized function of skeletal muscle? 1) A) guard body entrances and exits
B) maintain posture
C) maintain body
... [Show More] temperature
D) produce movement
E) all of the above
2) Nerves and blood vessels that service the muscle fibers are located in the connective tissues of the 2) A) myofibrils.
B) sarcolemma.
C) endomysium.
D) sarcomere.
E) perimysium.
3) Which of the following best describes the term sarcoplasmic reticulum? 3) A) largely made of myosin molecules
B) storage and release site for calcium ions
C) thin filaments are anchored here
D) protein that accounts for elasticity of resting muscle
E) repeating unit of striated myofibrils
4) Interactions between actin and myosin filaments of the sarcomere are responsible for 4) A) the conduction of neural stimulation to the muscle fiber.
B) muscle fatigue.
C) the striped appearance of skeletal muscle.
D) muscle contraction.
E) muscle relaxation.
5) 5)
6) A t rest, active sites on the actin are blocked by 6)
A) calcium ions.
B) troponin molecules.
C) tropomyosin molecules.
D) myosin molecules.
E) A TP molecules.
7) Cross- bridges are portions of 7)
A) actin molecules.
B) myosin molecules.
C) tropomyosin molecules.
D) troponin molecules.
E) calcium ions.
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8) When a skeletal muscle fiber contracts, 8)
A) the zones of overlap get larger.
B) the H bands and I bands get smaller.
C) the Z lines get closer together.
D) the width of the A band remains constant.
E) all of the above
9) The following is a list of the events that occur during a muscle contraction. 9)
1. M yosin cross- bridges bind to the actin.
2. The free myosin head splits A TP.
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 A TP molecule and detaches from the actin.
The correct sequence of these events is
A) 3, 5, 1, 2, 4, 6.
B) 1, 4, 6, 2, 3, 5.
C) 1, 3, 5, 4, 6, 2.
D) 5, 1, 4, 6, 2, 3.
E) 3, 5, 1, 4, 6, 2.
Figure 9-1 Skeletal M uscle Fiber
Use Figure 9-1 to answer the following questions:
10) W hat is released from the structure labeled "9"? 10)
A) acetylcholinesterase
B) sarcoplasm
C) calcium ions
D) acetylcholine
E) protein
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11) Active sites on the actin become available for binding after 11) A) troponin binds to tropomyosin.
B) calcium binds to tropomyosin.
C) myosin binds to troponin.
D) calcium binds to troponin.
E) actin binds to troponin.
Figure 9-1 Skeletal M uscle Fiber
Use Figure 9-1 to answer the following questions:
12) 12)
13) 13)
14) In an isotonic contraction, 14)
A) muscle tension exceeds the load and the muscle lifts the load.
B) many twitches fuse into one.
C) tension rises and falls but the muscle length is constant.
D) flexion is produced.
E) the peak tension is less than the load.
15) D uring anaerobic glycolysis 15)
A) oxygen is not consumed.
B) pyruvic acid is produced.
C) A TP is produced.
D) all of the above
E) B and C only
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16) The type of muscle fiber that is most resistant to fatigue is the fiber. 16) A) intermediate
B) fast
C) high- density
D) anaerobic
E) slow
17) Shortening a muscle while it maintains constant tension is called ________. 17) A) complete tetanus
B) an isometric contraction
C) an isotonic contraction
D) incomplete tetanus
E) an isokinetic contraction
18) Which of the following is not a characteristic of a muscle cell? 18) A) Conductivity
B) Excitability
C) Contractility
D) Plasticity
E) Extensibility
19) The most common lever systems in the body are those that have the applied force between the
fulcrum and the load. These are called levers.
A) fourth - class
B) second - class
C) fifth - class
D) third - class
E) first- class
19)
20) Contracting the gastrocnemius muscles to elevate the body on the toes involves a lever. 20)
A) fourth - class
B) third - class
C) first- class
D) second - class
E) both B and C
21) A muscle that inserts on the body of the mandible is probably involved in 21) A) chewing.
B) blow ing.
C) spitting.
D) kissing.
E) frowning.
22) A muscle that assists the muscle that is primarily responsible for a given action is a(n) 22) A) antagonist.
B) originator.
C) levator.
D) agonist.
E) synergist.
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23) A(n) _ is a muscle whose contraction is chiefly responsible for producing a particular movement.
A) prime mover
B) agonist
C) antagonist
D) all of the above
E) A or B only [Show Less]