Question 1

Explain the process of anaerobic respiration in the muscle. What is the oxygen debt, and how is it "repaid"?

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Question 2

List and describe the three general functions of skeletal muscle tissue.

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Question 3

Match each term with its corresponding description regarding the sliding-filament theory.
-Protein that has receptor sites for an ion that causes it to change shape and pull another protein away from the receptor sites on the actin

Accepted Answer

Troponin is the protein that binds calcium ions, causing it to change shape and move tropomyosin away from actin's binding sites, allowing muscle contraction to occur.

Question 4

Name and describe the myofilament fibers in the sarcomere.

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Question 5

Match each term with its corresponding description regarding the sliding-filament theory.
-Protein that directly prevents the formation of cross-bridges in the sarcomere

Accepted Answer

Tropomyosin binds to actin and blocks the binding site for myosin on actin, preventing the formation of cross-bridges in the absence of calcium.

Answer: A
 Troponin is the protein complex that binds calcium ions and moves tropomyosin out of the way, exposing the myosin-binding sites on actin.

Answer: G
 Cross-bridges are the connections formed between myosin heads and actin filaments during muscle contraction.

Answer: F
 Calcium ions bind to troponin, causing a conformational change in the troponin-tropomyosin complex, which allows the myosin-binding sites on actin to be exposed.

Answer: B
 Myosin is the motor protein that binds to actin and moves the actin filaments relative to the myosin filaments, which results in muscle contraction.

Answer: C
 Actin is the thin filament that, along with myosin, makes up the muscle sarcomere.

Answer: E
 ATP provides the energy needed for myosin to bind to actin and move the actin filaments relative to the myosin filaments.

Answer: D
 T-tubules are invaginations of the muscle cell membrane that help to transmit the action potential deep into the muscle fiber, triggering the release of calcium ions from the sarcoplasmic reticulum.

Answer: I
 Acetylcholine is a neurotransmitter that is released by motor neurons at the neuromuscular junction and binds to receptors on the muscle fiber sarcolemma, triggering an action potential that leads to muscle contraction.

Question 6

List three conditions that influence the strength of muscle contraction.

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Question 7

Explain how glycogen and myoglobin aid in muscle contraction.

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Question 8

Describe and/or diagram the sarcomere.

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Question 9

Define rigor mortis. Why does it occur?

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Question 10

Explain what is meant by the graded strength principle of muscle contraction.

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Question 11

Match each term with its corresponding description regarding the sliding-filament theory.
-Protein that has cross-bridge heads that pull on the thin fiber

Accepted Answer

Myosin is the protein that has cross-bridge heads which interact with actin filaments to pull them, facilitating muscle contraction.

Question 12

Explain how the treppe, or staircase, phenomenon applies to pre-exercise warm-up.

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Question 13

Match each term with its corresponding description regarding the sliding-filament theory.
-Ion that is released by the sarcoplasmic reticulum

Accepted Answer

Calcium is released by the sarcoplasmic reticulum, which triggers the binding of myosin to actin.

Answer: G 
 Cross-bridges are formed by the binding of myosin to actin during muscle contraction.

Answer: I 
 Acetylcholine is a neurotransmitter released by motor neurons that initiates muscle contraction by triggering the release of calcium from the sarcoplasmic reticulum.

Note: The other terms have important roles in the sliding-filament theory as well, but they do not directly correspond to the given description.

Question 14

Differentiate among slow, fast, and intermediate fibers.

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Question 15

Explain the role of ATP in muscle contraction.

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Question 16

Match each term with its corresponding description regarding the sliding-filament theory.
-Compound that supplies the energy for muscle contraction

Accepted Answer

ATP supplies the energy for muscle contraction.

Answer: F
 Calcium triggers muscle contraction by binding to troponin.

Answer: B
 Myosin forms cross-bridges with actin filaments, which results in muscle contraction.

Answer: D
 T-tubules are invaginations in the sarcolemma that allow for rapid transmission of muscle impulses.

Answer: A
 Troponin is a protein complex that is important in regulating muscle contraction by binding to calcium.

Answer: G
 Cross-bridges are formed when myosin heads bind to actin filaments and pull them closer together.

Answer: H
 Tropomyosin is a protein that wraps around actin filaments and helps regulate muscle contraction by blocking the myosin-binding sites.

Answer: I
 Acetylcholine is a neurotransmitter that is released at the neuromuscular junction and initiates muscle contraction by binding to receptors on the sarcolemma.

Question 17

Describe the physiological process of muscle contraction.

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Question 18

Match each term with its corresponding description regarding the sliding-filament theory.
-Chemical released by the motor neuron that initiates the stimulus for a muscle contraction

Accepted Answer

Acetylcholine is the chemical released by the motor neuron that initiates the stimulus for a muscle contraction.

Answer: F
 Calcium is the ion that binds to troponin, causing a shift in the position of tropomyosin, which then exposes the binding sites on the actin filament for the myosin heads to attach, leading to muscle contraction.

Answer: E
 ATP is the primary source of energy for muscle contraction, providing the energy needed for the myosin heads to detach from actin and for the repositioning of the cross-bridges during the contraction cycle.

Answer: G
 Cross-bridges form between the myosin heads and the exposed binding sites on the actin filament, and their movement during the contraction cycle pulls the actin filament closer to the center of the sarcomere, causing muscle contraction.

Answer: A and H
 Troponin and tropomyosin work together to regulate muscle contraction by blocking or allowing the attachment of myosin heads to actin, depending on the presence or absence of calcium ions.

Question 19

Explain the role of the skeletal muscles in heat production for the body.

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Question 20

List three characteristics of muscles.

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Quiz 17: Muscle Contraction