Question 1

Which of the following best describes the structure and function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

It is a modified endoplasmic reticulum that forms a web-like network around myofibrils and releases calcium ions during muscle contraction.

Question 2

Which of the following is a distinguishing feature of cardiac muscle tissue compared to skeletal and smooth muscle?

Accepted Answer

It is striated, branched, and connected by gap junctions.

Question 3

During the sliding filament mechanism of contraction, which event occurs within the sarcomere?

Accepted Answer

The Z-discs move closer together as thin filaments slide toward the M line.

Question 4

Which of the following best explains how the resting membrane potential is established in skeletal myocytes?

Accepted Answer

By the active transport of sodium and potassium ions via the sodium-potassium pump, creating a negative potential inside the cell.

Question 5

A patient presents with muscle weakness. Laboratory tests reveal a defect in the protein titin. Which of the following consequences is most likely?

Accepted Answer

Impaired stabilization of myofibrils and increased susceptibility to muscle overstretching.

Question 6

Which of the following correctly matches the muscle type with its primary function and location?

Accepted Answer

Cardiac muscle: involuntary contraction; walls of the heart

Question 7

Which structural component of skeletal muscle is responsible for conducting action potentials deep into the muscle fiber?

Accepted Answer

Transverse (T) tubules

Question 8

A researcher is studying the arrangement of myofilaments in a sarcomere. Which region contains only thick filaments and no thin filaments?

Accepted Answer

H zone

Question 9

Which of the following best describes the role of the endomysium in skeletal muscle tissue?

Accepted Answer

It surrounds individual muscle fibers and holds them together within the muscle tissue.

Question 10

A toxin blocks the sodium-potassium pump in skeletal muscle cells. What is the most immediate effect on the resting membrane potential?

Accepted Answer

The resting membrane potential moves toward zero (depolarizes).

Question 11

Which of the following is true regarding the arrangement of connective tissue in a skeletal muscle organ?

Accepted Answer

The epimysium surrounds the entire muscle and continues as a tendon.

Question 12

Which of the following best explains why skeletal muscle fibers are multinucleated?

Accepted Answer

They are formed by the fusion of multiple myoblasts during development.

Question 13

During muscle contraction, which of the following changes occur in the sarcomere?

Accepted Answer

The I band and H zone both decrease in width.

Question 14

Which of the following is a property shared by all three types of muscle tissue?

Accepted Answer

They all generate muscle tension.

Question 15

A patient has a genetic mutation that prevents the formation of gap junctions in cardiac muscle. Which of the following is the most likely consequence?

Accepted Answer

Impaired electrical conduction between cardiac muscle cells, leading to arrhythmias.

Question 16

Which of the following best describes the function of elastic filaments (titin) in the sarcomere?

Accepted Answer

They stabilize the myofibril structure and resist excessive stretching.

Question 17

Which of the following equations correctly represents the voltage (V) across the sarcolemma at resting membrane potential?

Accepted Answer

$$V = V_{inside} - V_{outside}$$

Question 18

Which of the following best describes the role of the Z disc in the sarcomere?

Accepted Answer

It anchors thin filaments and serves as the boundary between adjacent sarcomeres.

Muscle Tissue I: Structure, Function, and Physiology

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