Question 1

Which of the following best describes the main function of muscle tissue in the human body?

Accepted Answer

To transform chemical energy (ATP) into directed mechanical energy capable of exerting force

Question 2

Which characteristic is shared by all three types of muscle tissue?

Accepted Answer

Excitability (responsiveness)

Question 3

A patient presents with muscle weakness and drooping eyelids. Laboratory tests reveal antibodies against acetylcholine receptors. Which process is most directly impaired?

Accepted Answer

Generation of an action potential at the neuromuscular junction

Question 4

Which connective tissue sheath surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 5

During the sliding filament model of contraction, what happens to the H zone of the sarcomere?

Accepted Answer

It disappears as thin filaments slide toward the M line

Question 6

Which protein directly binds calcium to initiate muscle contraction in skeletal muscle?

Accepted Answer

Troponin

Question 7

A muscle fiber is unable to relax after contraction due to a lack of ATP. Which condition does this describe?

Accepted Answer

Rigor mortis

Question 8

Which of the following equations correctly represents the direct phosphorylation of ADP by creatine phosphate?

Accepted Answer

$$\mathrm{Creatine\ phosphate + ADP \rightarrow Creatine + ATP}$$

Question 9

Which type of muscle contraction occurs when muscle tension increases but the muscle does not change length?

Accepted Answer

Isometric contraction

Question 10

What is the role of the T tubules in skeletal muscle fibers?

Accepted Answer

They allow electrical nerve transmissions to reach deep into the muscle fiber

Question 11

Which of the following best explains why muscle fibers experience fatigue during prolonged, high-intensity exercise?

Accepted Answer

Ionic imbalances and increased inorganic phosphate interfere with calcium release and cross bridge cycling

Question 12

Which of the following is true regarding the arrangement of myofilaments in a sarcomere?

Accepted Answer

Thin filaments are anchored to the Z disc and thick filaments are connected at the M line

Question 13

A drug that blocks voltage-gated calcium channels at the axon terminal of a motor neuron would have which effect?

Accepted Answer

Prevent release of acetylcholine into the synaptic cleft

Question 14

Which of the following best describes the 'power stroke' in the cross bridge cycle?

Accepted Answer

Myosin head pivots and pulls thin filament toward the M line

Question 15

Which of the following is a function of muscle tone?

Accepted Answer

It keeps muscles firm, healthy, and ready to respond

Question 16

Which of the following best describes the role of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It degrades acetylcholine, terminating the signal at the synaptic cleft

Question 17

Which of the following is the correct sequence of events for skeletal muscle contraction?

Accepted Answer

Events at neuromuscular junction → Muscle fiber excitation → Excitation-contraction coupling → Cross bridge cycling

Question 18

Which of the following best explains why the sarcolemma must repolarize after an action potential?

Accepted Answer

To restore ionic conditions and allow the muscle fiber to be stimulated again

Question 19

Which of the following is a correct statement about the energy systems used during exercise?

Accepted Answer

Anaerobic glycolysis produces ATP more rapidly than aerobic respiration but yields less ATP per glucose molecule

Muscles and Muscle Tissue: Structure, Function, and Physiology

Guida di studio - Domande di pratica

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