Question 1

Which of the following is NOT a characteristic shared by all three types of muscle tissue (skeletal, cardiac, and smooth)?

Accepted Answer

Voluntary control via the somatic nervous system

Question 2

A patient is unable to move their arm due to a failure in the release of acetylcholine at the neuromuscular junction. Which step in muscle excitation is directly affected?

Accepted Answer

Motor neuron stimulation and neurotransmitter release

Question 3

Which connective tissue layer surrounds an individual muscle fiber?

Accepted Answer

Endomysium

Question 4

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

Accepted Answer

Propagation of the action potential along the T-tubules

Question 5

Which equation correctly represents the net ATP yield from aerobic metabolism of one glucose molecule in skeletal muscle?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O + 32ATP$$

Question 6

A muscle fiber is stimulated twice in rapid succession before it has fully relaxed. What is this phenomenon called?

Accepted Answer

Summation

Question 7

Which of the following best describes the role of the sarcoplasmic reticulum in muscle contraction?

Accepted Answer

It stores and releases calcium ions required for contraction

Question 8

Which step in the cross-bridge cycle is directly powered by the hydrolysis of ATP?

Accepted Answer

Cocking of the myosin head into its high-energy position

Question 9

A muscle is contracting and the tension exceeds the load, causing the muscle to shorten. What type of contraction is this?

Accepted Answer

Concentric contraction

Question 10

Which of the following mechanisms provides the fastest way for skeletal muscle fibers to regenerate ATP during intense, short-duration exercise?

Accepted Answer

Direct phosphorylation by creatine phosphate

Question 11

What is the function of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine, terminating the signal at the synapse

Question 12

Which of the following best explains why rigor mortis occurs after death?

Accepted Answer

ATP is no longer produced, preventing myosin head detachment from actin

Question 13

Which structure in skeletal muscle is responsible for conducting action potentials deep into the muscle fiber?

Accepted Answer

T-tubules

Question 14

A muscle fiber is unable to contract even though an action potential is present on the sarcolemma. Which of the following is the most likely cause?

Accepted Answer

Defective voltage-gated calcium channels in the sarcoplasmic reticulum

Question 15

Which of the following best describes the relationship between the number of motor units activated and the strength of muscle contraction?

Accepted Answer

Increasing the number of motor units activated increases contraction strength

Question 16

Which phase of a muscle twitch is characterized by the release of calcium from the sarcoplasmic reticulum and the beginning of cross-bridge cycling?

Accepted Answer

Latent period

Question 17

Which of the following is a function of the perimysium in skeletal muscle?

Accepted Answer

Surrounds bundles of muscle fibers (fascicles)

Question 18

Which of the following events occurs first during excitation-contraction coupling in skeletal muscle?

Accepted Answer

Action potential travels along the sarcolemma

Question 19

A patient presents with muscle weakness due to a genetic defect in the dystrophin protein. Which structure is most directly affected?

Accepted Answer

Sarcolemma

Question 20

Which of the following best describes the difference between isotonic and isometric contractions?

Accepted Answer

Isotonic contractions involve muscle shortening or lengthening with constant tension

Chapter 9: Muscles and Muscle Tissue – Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard