Chapter 9 – The Muscular System: Skeletal Muscle Tissue and Muscle Organization

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Anatomy of Skeletal Muscles

Muscle Contraction

Motor Unit and Muscle Fiber Types

Muscle Fiber Organization

& Muscle Terminology

Levers & Pulleys / Aging

Effects on Muscles

FINAL ROUND

Topic 1:

$100 Question

Which of the following connective tissues divides the muscle into a series of internal compartments with fascicles?

a. epimysium

b. endomysium

c. aponeuroses

d. perimysiumBACK TO GAME

ANSWER

Topic 1:

$100 Answer

Which of the following connective tissues divides the muscle into a series of internal compartments with fascicles?

a. epimysium

b. endomysium

c. aponeuroses

d. perimysiumBACK TO GAME

Topic 1:

$200 Question

Which protein type holds the F-actin strand together in each thin filament?

a. actinins

b. nebulin

c. titin

d. G-actinBACK TO GAME

ANSWER

Topic 1:

$200 Answer

Which protein type holds the F-actin strand together in each thin filament?

a. actinins

b. nebulin

c. titin

d. G-actinBACK TO GAME

Topic 1:

$300 Question

Each myofibril consists of a linear series of approximately how many sarcomeres?

a. 100

b. 1000

c. 10,000

d. 100,000BACK TO GAME

ANSWER

Topic 1:

$300 Answer

Each myofibril consists of a linear series of approximately how many sarcomeres?

a. 100

b. 1000

c. 10,000

d. 100,000BACK TO GAME

Topic 1:

$400 Question

Which of the following statements regarding thin filaments is false?

a. Each thin filament consists of a twisted strand 5-6 μm in diameter and 1 μm in length.

b. A slender strand of the protein “nebulin” holds the F-actin strand together.

c. At either end of the sarcomere, the thin filaments are attached to the Z line (Z disk).

d. None of the above statements is false.BACK TO GAMEANSWER

Topic 1:

$400 Answer

Which of the following statements regarding thin filaments is false?

a. Each thin filament consists of a twisted strand 5-6 μm in diameter and 1 μm in length.

b. A slender strand of the protein “nebulin” holds the F-actin strand together.

c. At either end of the sarcomere, the thin filaments are attached to the Z line (Z disk).

d. None of the above statements is false.BACK TO GAME

Topic 1:

$500 Question

Which of the following statements regarding the protein “titin” is/are true?

a. Each thin filament has a core of titin.

b. On either side of the M line, a strand of titin extends the length of the filament and continues to an attachment at the Z line.

c. The portion of the titin strand exposed within the I band is highly elastic and will recoil after stretching.

d. B and CBACK TO GAME

ANSWER

Topic 1:

$500 Answer

Which of the following statements regarding the protein “titin” is/are true?

a. Each thin filament has a core of titin.

b. On either side of the M line, a strand of titin extends the length of the filament and continues to an attachment at the Z line.

c. The portion of the titin strand exposed within the I band is highly elastic and will recoil after stretching.

d. b and cBACK TO GAME

Topic 2:

$100 Question

The ability of a muscle to contract over a range of resting lengths is known as the property of:

a. contraction

b. extensibility

c. elasticity

d. excitabilityBACK TO GAME

ANSWER

Topic 2:

$100 Answer

The ability of a muscle to contract over a range of resting lengths is known as the property of:

a. contraction

b. extensibility

c. elasticity

d. excitabilityBACK TO GAME

Topic 2:

$200 Question

Which of the following statements does not accurately apply to the process of muscular contraction?

a. The sarcoplasmic reticulum releases stored calcium ions during the initiation of contraction.

b. Calcium ions bind to tropomyosin, producing a change in the orientation of the troponin-tropomyosin complex that exposes active sites on the thin filament.

c. When calcium ion concentrations approach normal resting levels, the troponin-tropomyosin complex returns to its normal position.

d. Filament sliding and muscle fiber shortening are a result of repeated cycles of across-bridge binding, pivoting and detachment.

BACK TO GAMEANSWER

Topic 2:

$200 Answer

Which of the following statements does not accurately apply to the process of muscular contraction?

a. The sarcoplasmic reticulum releases stored calcium ions during the initiation of contraction.

b. Calcium ions bind to tropomyosin, producing a change in the orientation of the troponin-tropomyosin complex that exposes active sites on the thin filament.

c. When calcium ion concentrations approach normal resting levels, the troponin-tropomyosin complex returns to its normal position.

d. Filament sliding and muscle fiber shortening are a result of repeated cycles of across-bridge binding, pivoting and detachment.

BACK TO GAME

Topic 2:

$300 Question

Which of the following statements regarding the start of a contraction is false?

a. The immediate trigger for contraction is the appearance of free calcium ions in the sarcoplasm.

b. Electrical events at the sarcolemmal surface cause a contraction by triggering the release of calcium ions from the T tubules.

c. Calcium ions diffuse into the zone of overlap, where they bind to troponin.

d. The contraction begins after the position of the tropomyosin strand has been altered, exposing the active sites on the actin molecules for cross-bridge binding.

BACK TO GAMEANSWER

Topic 2:

$300 Answer

Which of the following statements regarding the start of a contraction is false?

a. The immediate trigger for contraction is the appearance of free calcium ions in the sarcoplasm.

b. Electrical events at the sarcolemmal surface cause a contraction by triggering the release of calcium ions from the T tubules.

c. Calcium ions diffuse into the zone of overlap, where they bind to troponin.

d. The contraction begins after the position of the tropomyosin strand has been altered, exposing the active sites on the actin molecules for cross-bridge binding.

BACK TO GAME

Topic 2:

$400 Question

Which of the following statements regarding the end of a contraction is true?

a. The duration of the contraction is usually independent of the duration of electrical stimulation.

b. If the electrical stimulation ceases, the transverse tubules will recapture the calcium ions.

c. Muscle contraction is a passive process since muscles cannot push; they can only pull.

d. The change in calcium permeability at the terminal cisternae is temporary, so additional electrical impulses must be conducted along the T tubules if the contraction is to continue.

BACK TO GAMEANSWER

Topic 2:

$400 Answer

Which of the following statements regarding the end of a contraction is true?

a. The duration of the contraction is usually independent of the duration of electrical stimulation.

b. If the electrical stimulation ceases, the transverse tubules will recapture the calcium ions.

c. Muscle contraction is a passive process since muscles cannot push; they can only pull.

d. The change in calcium permeability at the terminal cisternae is temporary, so additional electrical impulses must be conducted along the T tubules if the contraction is to continue.

BACK TO GAME

Topic 2:

$500 Question

Which of the following statements regarding the effect of sarcomere length on tension is incorrect?

a. When sarcomeres are too short, contractions cannot occur because either the thick filaments come in contact with Z lines, or the thin filaments overlap across the center of the sarcomere.

b. The tension produced by a contracting skeletal muscle fiber reaches a maximum when the zone of overlap is large and the thin filaments extend across the center of the sarcomere.

c. If the sarcomeres are stretched too far, the zone of overlap is reduced, or disappears, and the cross-bridge interactions are reduced or cannot occur.

d. None of the above statements is incorrect.BACK TO GAMEANSWER

Topic 2:

$500 Answer

Which of the following statements regarding the effect of sarcomere length on tension is incorrect?

a. When sarcomeres are too short, contractions cannot occur because either the thick filaments come in contact with Z lines, or the thin filaments overlap across the center of the sarcomere.

b. The tension produced by a contracting skeletal muscle fiber reaches a maximum when the zone of overlap is large and the thin filaments extend across the center of the sarcomere.

c. If the sarcomeres are stretched too far, the zone of overlap is reduced, or disappears, and the cross-bridge interactions are reduced or cannot occur.

d. None of the above statements is incorrect.BACK TO GAME

Topic 3:

$100 Question

Which of the following is/are not characteristic of slow fibers?

a. They have high myoglobin content.

b. They contain a relatively large number of mitochondria.

c. The tension produced by their muscle fibers is very high, resulting in powerful contractions.

d. Their fiber diameter is small compared to that of fast fibers.

BACK TO GAMEANSWER

Topic 3:

$100 Answer

Which of the following is/are not characteristic of slow fibers?

a. They have high myoglobin content.

b. They contain a relatively large number of mitochondria.

c. The tension produced by their muscle fibers is very high, resulting in powerful contractions.

d. Their fiber diameter is small compared to that of fast fibers.

BACK TO GAME

Topic 3:

$200 Question

Which of the following statements regarding motor units and muscle control is false?

a. The amount of tension produced when a skeletal muscle contracts depends on (1) the frequency of stimulation; and (2) the number of motor units involved.

b. Each muscle fiber experiences a range of contraction, since not all of the fibers in a motor unit contract at the same time.

c. When a decision is made to perform a movement, specific groups of motor neurons are stimulated.

d. The size of a motor unit is an indication of how fine the control of movement can be.

BACK TO GAMEANSWER

Topic 3:

$200 Answer

Which of the following statements regarding motor units and muscle control is false?

a. The amount of tension produced when a skeletal muscle contracts depends on (1) the frequency of stimulation; and (2) the number of motor units involved.

b. Each muscle fiber experiences a range of contraction, since not all of the fibers in a motor unit contract at the same time.

c. When a decision is made to perform a movement, specific groups of motor neurons are stimulated.

d. The size of a motor unit is an indication of how fine the control of movement can be.

BACK TO GAME

Topic 3:

$300 Question

Which of the following statements refer(s) to white fibers?

a. They are specialized to continue contracting for long periods without fatigue.

b. They contain densely packed myofibrils.

c. They contain relatively few mitochondria.

d. b and c

BACK TO GAME

ANSWER

Topic 3:

$300 Answer

Which of the following statements refer(s) to white fibers?

a. They are specialized to continue contracting for long periods without fatigue.

b. They contain densely packed myofibrils.

c. They contain relatively few mitochondria.

d. b and c

BACK TO GAME

Topic 3:

$400 Question

Which type of muscle has the most extensive capillary network, relative to other muscle types?

a. Skeletal muscles containing slow muscle fibers.

b. Skeletal muscles containing fast muscle fibers.

c. Skeletal muscles containing intermediate muscle fibers.

d. Skeletal muscles containing large glycogen reserves.

BACK TO GAMEANSWER

Topic 3:

$400 Answer

Which type of muscle has the most extensive capillary network, relative to other muscle types?

a. Skeletal muscles containing slow muscle fibers.

b. Skeletal muscles containing fast muscle fibers.

c. Skeletal muscles containing intermediate muscle fibers.

d. Skeletal muscles containing large glycogen reserves.

BACK TO GAME

Topic 3:

$500 Question

Which of the following statements regarding fast skeletal muscle fibers is true?

a. They have low fatigue resistance.

b. They are white in color.

c. They have few mitochondria.

d. All of the above are true.BACK TO GAME

ANSWER

Topic 3:

$500 Answer

Which of the following statements regarding fast skeletal muscle fibers is true?

a. They have low fatigue resistance.

b. They are white in color.

c. They have few mitochondria.

d. All of the above are true.BACK TO GAME

Topic 4:

$100 Question

A long muscle that extends the fingers, the extensor digitorum muscle, has all of the muscle cells on the same side of the tendon. This is known as which type of skeletal muscle organization?

a. bipennate

b. unipennate

c. multipennate

d. parallelBACK TO GAME

ANSWER

Topic 4:

$100 Answer

A long muscle that extends the fingers, the extensor digitorum muscle, has all of the muscle cells on the same side of the tendon. This is known as which type of skeletal muscle organization?

a. bipennate

b. unipennate

c. multipennate

d. parallelBACK TO GAME

Topic 4:

$200 Question

A parallel skeletal muscle 6.45 cm2 (1 in2) in cross-sectional area can develop approximately how much tension?

a. 2.3 kg (5 lb)

b. 23 kg (50 lb)

c. 46 kg (100 lb)

d. 230 kg (500 lb)BACK TO GAME

ANSWER

Topic 4:

$200 Answer

A parallel skeletal muscle 6.45 cm2 (1 in2) in cross-sectional area can develop approximately how much tension?

a. 2.3 kg (5 lb)

b. 23 kg (50 lb)

c. 46 kg (100 lb)

d. 230 kg (500 lb)BACK TO GAME

Topic 4:

$300 Question

Regarding muscle terminology, which of the following terms indicates that the muscle if “pear-shaped”?

a. piriformis

b. splenius

c. serratus

d. teresBACK TO GAME

ANSWER

Topic 4:

$300 Answer

Regarding muscle terminology, which of the following terms indicates that the muscle if “pear-shaped”?

a. piriformis

b. splenius

c. serratus

d. teresBACK TO GAME

Topic 4:

$400 Question

Which of the following statements regarding origins and insertions is false?

a. If there are several tendons at one end and just one at the other, there are multiple origins and a single insertion.

b. If a muscle extends between a broad aponeurosis and a narrow tendon, the tendon is considered to be the origin, and the aponeurosis is attached to the insertion.

c. Both statements are false.

d. Neither statement is false.BACK TO GAME

ANSWER

Topic 4:

$400 Answer

Which of the following statements regarding origins and insertions is false?

a. If there are several tendons at one end and just one at the other, there are multiple origins and a single insertion.

b. If a muscle extends between a broad aponeurosis and a narrow tendon, the tendon is considered to be the origin, and the aponeurosis is attached to the insertion.

c. Both statements are false.

d. Neither statement is false.BACK TO GAME

Topic 4:

$500 Question

Synergists may assist agonists by preventing movement at a joint, and thereby stabilizing the origin of the agonist; these muscles are called:

a. antagonists

b. reverse agonists

c. prime movers

d. fixatorsBACK TO GAME

ANSWER

Topic 4:

$500 Answer

Synergists may assist agonists by preventing movement at a joint, and thereby stabilizing the origin of the agonist; these muscles are called:

a. antagonists

b. reverse agonists

c. prime movers

d. fixatorsBACK TO GAME

Topic 5:

$100 Question

Which of the following is/(are) an example/(s) of “anatomical pulleys?”

a. lateral malleolus of fibula

b. patella

c. capitulum of humerus

d. a and bBACK TO GAME

ANSWER

Topic 5:

$100 Answer

Which of the following is/(are) an example/(s) of “anatomical pulleys?”

a. lateral malleolus of fibula

b. patella

c. capitulum of humerus

d. a and bBACK TO GAME

Topic 5:

$200 Question

In which lever class is the resistance located between the applied force and the fulcrum?

a. first-class levers

b. second-class levers

c. third-class levers

d. anatomical pulleysBACK TO GAME

ANSWER

Topic 5:

$200 Answer

In which lever class is the resistance located between the applied force and the fulcrum?

a. first-class levers

b. second-class levers

c. third-class levers

d. anatomical pulleysBACK TO GAME

Topic 5:

$300 Question

Which of the following effects of aging on the muscular system is inaccurate?

a. The amount of fibrous tissue decreases with age, resulting in limited repair capabilities.

b. Skeletal muscles develop fibrosis, making the muscle less flexible and less elastic.

c. A lower tolerance for exercise results in part form the reduction in the ability to eliminate the heat generated during muscular contraction.

d. Skeletal muscle fibers’ diameter decrease in size, primarily due to a reduction in the number of myofibrils.

BACK TO GAMEANSWER

Topic 5:

$300 Answer

Which of the following effects of aging on the muscular system is inaccurate?

a. The amount of fibrous tissue decreases with age, resulting in limited repair capabilities.

b. Skeletal muscles develop fibrosis, making the muscle less flexible and less elastic.

c. A lower tolerance for exercise results in part form the reduction in the ability to eliminate the heat generated during muscular contraction.

d. Skeletal muscle fibers’ diameter decrease in size, primarily due to a reduction in the number of myofibrils.

BACK TO GAME

Topic 5:

$400 Question

Which of the following statements regarding aging and the muscular system is false?

a. Regular exercise is more important than extremely demanding exercise in maintaining a healthy musculoskeletal system.

b. The number of myosatellite cells steadily decrease with age.

c. Fibrosis makes muscles less flexible, and collagen fibers can restrict movement and circulation.

d. The rate of decline in muscular performance is different in all individuals, depending upon exercise patterns and lifestyle.

BACK TO GAMEANSWER

Topic 5:

$400 Answer

Which of the following statements regarding aging and the muscular system is false?

a. Regular exercise is more important than extremely demanding exercise in maintaining a healthy musculoskeletal system.

b. The number of myosatellite cells steadily decrease with age.

c. Fibrosis makes muscles less flexible, and collagen fibers can restrict movement and circulation.

d. The rate of decline in muscular performance is different in all individuals, depending upon exercise patterns and lifestyle.

BACK TO GAME

Topic 5:

$500 Question

The muscles which extend the neck are examples of which type of lever?

a. first-class lever, in which the fulcrum lies between the applied force and the resistance

b. second-class lever, in which the resistance is located between the applied force and the fulcrum

c. third-class lever, in which the force is applied between the applied force and the fulcrum

d. first-class lever, in which the resistance is located between the applied force and the fulcrum

BACK TO GAMEANSWER

Topic 5:

$500 Answer

The muscles which extend the neck are examples of which type of lever?

a. first-class lever, in which the fulcrum lies between the applied force and the resistance

b. second-class lever, in which the resistance is located between the applied force and the fulcrum

c. third-class lever, in which the force is applied between the applied force and the fulcrum

d. first-class lever, in which the resistance is located between the applied force and the fulcrum

BACK TO GAME

FINAL ROUND Question

Identify the correct sequence of steps in the initiation of a muscle contraction:

1 - Calcium ions bind to troponin, producing a change in the orientation of the troponin-tropomyosin complex that exposes the active sites on the thin filaments.

2 – The change in transmembrane potential of the muscle fiber leads to the production of an action potential that spreads across its entire surface and along the T tubules.

3 – Repeated cycles of cross-bridge binding, pivoting, and detachment occur, powered by the hydrolysis of ATP.

4 – The sarcoplasmic reticulum (SR) releases stored calcium ions, increasing the calcium concentration of the sarcoplasm in and around the sarcomere.

5 – At the neuromuscular synapse, ACh released by the synaptic terminal binds to receptors on the sarcolemma.

a. 2-4-5-1-3

b. 2-4-1-3-5

c. 5-2-4-1-3

d. 5-4-2-1-3BACK TO GAME

ANSWER

FINAL ROUND Answer

Identify the correct sequence of steps in the initiation of a muscle contraction:

1 - Calcium ions bind to troponin, producing a change in the orientation of the troponin-tropomyosin complex that exposes the active sites on the thin filaments.

2 – The change in transmembrane potential of the muscle fiber leads to the production of an action potential that spreads across its entire surface and along the T tubules.

3 – Repeated cycles of cross-bridge binding, pivoting, and detachment occur, powered by the hydrolysis of ATP.

4 – The sarcoplasmic reticulum (SR) releases stored calcium ions, increasing the calcium concentration of the sarcoplasm in and around the sarcomere.

5 – At the neuromuscular synapse, ACh released by the synaptic terminal binds to receptors on the sarcolemma.

a. 2-4-5-1-3

b. 2-4-1-3-5

c. 5-2-4-1-3

d. 5-4-2-1-3BACK TO GAME