Question 1

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

Accepted Answer

It stores and releases calcium ions necessary for muscle contraction.

Question 2

During the sliding filament model of contraction, which of the following occurs?

Accepted Answer

Thin filaments slide past thick filaments, causing the sarcomere to shorten.

Question 3

A patient presents with muscle stiffness several hours after death. Which of the following best explains this phenomenon (rigor mortis)?

Accepted Answer

ATP is no longer produced, preventing detachment of myosin heads from actin.

Question 4

Which connective tissue sheath surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 5

Which of the following is the correct sequence of structures from superficial to deep in a skeletal muscle?

Accepted Answer

Epimysium → Perimysium → Endomysium → Muscle fiber → Myofibril → Myofilament

Question 6

Which type of muscle fiber is best suited for endurance activities such as marathon running?

Accepted Answer

Slow oxidative fibers

Question 7

A muscle contraction in which the muscle length does not change, but tension increases, is called:

Accepted Answer

Isometric contraction

Question 8

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

Accepted Answer

Action potential travels along the sarcolemma and down T tubules.

Question 9

Which of the following best explains why muscle fatigue occurs during intense exercise?

Accepted Answer

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

Question 10

Which of the following is true regarding the difference between skeletal and smooth muscle contraction?

Accepted Answer

Skeletal muscle contraction is regulated by troponin, while smooth muscle contraction is regulated by calmodulin.

Question 11

A muscle fiber is stimulated by a single action potential, resulting in a brief contraction followed by relaxation. This response is called:

Accepted Answer

Muscle twitch

Question 12

Which of the following best describes the function of T tubules in skeletal muscle fibers?

Accepted Answer

They conduct action potentials deep into the muscle fiber.

Question 13

Which of the following is the primary source of ATP during the first few seconds of intense muscle activity?

Accepted Answer

Creatine phosphate

Question 14

Which statement best explains the size principle of motor unit recruitment?

Accepted Answer

Smaller motor units are recruited first, followed by larger units as more force is needed.

Question 15

Which of the following is a characteristic unique to cardiac muscle tissue?

Accepted Answer

Branching chains of cells with intercalated discs

Question 16

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

Accepted Answer

It breaks down acetylcholine, terminating the signal for muscle contraction.

Question 17

Which of the following is a direct attachment of muscle to bone?

Accepted Answer

The epimysium fuses directly with the periosteum of bone.

Question 18

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

Accepted Answer

It stores oxygen for use during muscle contraction.

Question 19

Which of the following is true regarding the H zone of a sarcomere during muscle contraction?

Accepted Answer

The H zone shortens and may disappear as actin filaments slide inward.

Question 20

Which of the following is a function of muscle tone?

Accepted Answer

It keeps muscles firm, healthy, and ready to respond.

Muscles and Muscle Tissue: Structure, Function, and Contraction

Study Guide - Practice Questions