Q: Which equation correctly represents the breakdown of ATP during muscle contraction?

$$\mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \text{energy}$$

Question 1

Which property is shared by all muscle tissue types and allows them to respond to a stimulus by generating an action potential?

Accepted Answer

Excitability

Question 2

What is the main function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

Storing and releasing calcium ions

Question 3

During muscle contraction, which ion rushes into the axon terminal to trigger the release of neurotransmitter?

Accepted Answer

Calcium ($$\mathrm{Ca$$^{2+}$$})$$

Question 4

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 5

A patient is experiencing muscle weakness due to a lack of acetylcholine at the neuromuscular junction. Which step of muscle contraction is directly affected?

Accepted Answer

Transmission of the action potential across the synaptic cleft

Question 6

Which of the following best describes the role of myoglobin in skeletal muscle fibers?

Accepted Answer

Binds oxygen for aerobic metabolism

Question 7

Which phase of a muscle twitch is characterized by the time between stimulus and the onset of contraction, when excitation-contraction coupling occurs?

Accepted Answer

Latent period

Question 8

A marathon runner relies primarily on which type of muscle fiber, and what is its main energy source?

Accepted Answer

Slow-twitch; aerobic metabolism

Question 9

Which equation correctly represents the breakdown of ATP during muscle contraction?

Accepted Answer

$$\mathrm{ATP} ightarrow \mathrm{ADP} + \mathrm{P_i} + 	ext{energy}$$

Question 10

Which of the following best explains why cardiac muscle cannot undergo tetanus?

Accepted Answer

It has a long refractory period

Question 11

What is the functional unit of contraction in a skeletal muscle fiber?

Accepted Answer

Sarcomere

Question 12

Which process is responsible for the rapid generation of ATP during short, intense muscle activity?

Accepted Answer

Creatine phosphate breakdown

Question 13

During excitation-contraction coupling, what triggers the release of calcium ions from the sarcoplasmic reticulum?

Accepted Answer

Action potential traveling down the T-tubules

Question 14

Which of the following is a property of fast-twitch muscle fibers compared to slow-twitch fibers?

Accepted Answer

Greater diameter and more powerful contractions

Question 15

Which statement best describes the function of intercalated discs in cardiac muscle?

Accepted Answer

They allow rapid transmission of action potentials between cells

Question 16

A muscle fiber is unable to relax after repeated stimulation, resulting in a sustained contraction. What is this phenomenon called?

Accepted Answer

Complete tetanus

Question 17

Which of the following best explains why fatigue occurs during prolonged muscle activity?

Accepted Answer

Accumulation of lactic acid and depletion of ATP

Question 18

Which type of contraction occurs when a muscle changes length while maintaining constant tension, such as lifting a weight?

Accepted Answer

Isotonic

Question 19

Smooth muscle differs from skeletal muscle in that it:

Accepted Answer

Lacks striations

Question 20

A motor unit consists of:

Accepted Answer

A group of muscle fibers and the single motor neuron that innervates them

Muscle Tissue: Structure, Function, and Physiology

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