Question 1

Which of the following features is unique to cardiac muscle tissue and helps synchronize contraction between adjacent cells?

Accepted Answer

Intercalated discs

Question 2

A histology slide shows long, cylindrical fibers with multiple nuclei at the periphery and visible striations. Which muscle tissue is this most likely to be?

Accepted Answer

Skeletal muscle

Question 3

Which structure stores calcium ions and releases them during muscle contraction in skeletal muscle fibers?

Accepted Answer

Sarcoplasmic reticulum

Question 4

During muscle contraction, which of the following correctly describes the sequence of events at the neuromuscular junction?

Accepted Answer

Acetylcholine is released from the motor neuron, binds to receptors on the motor end plate, causing sodium influx

Question 5

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

Accepted Answer

They transmit action potentials deep into the muscle fiber

Question 6

A patient has a disorder affecting the sarcolemma of their muscle fibers. Which of the following processes would be most directly impaired?

Accepted Answer

Transmission of action potentials along the muscle cell membrane

Question 7

Which muscle tissue type is most likely to be found in the walls of the digestive tract, and what is its main histological feature?

Accepted Answer

Smooth muscle; non-striated, spindle-shaped cells

Question 8

Which of the following is the correct order of organization in skeletal muscle from largest to smallest?

Accepted Answer

Muscle (organ) → Fascicle → Muscle fiber → Myofibril

Question 9

A muscle fiber is exposed to a toxin that blocks acetylcholine receptors at the motor end plate. What is the most immediate effect?

Accepted Answer

Sodium cannot enter the muscle cell, preventing action potential generation

Question 10

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

Accepted Answer

They form from the fusion of multiple myoblasts during development

Question 11

If a mutation caused the sarcoplasmic reticulum to be unable to release calcium ions, which step in muscle contraction would be directly affected?

Accepted Answer

Binding of myosin to actin

Question 12

Which of the following structures is continuous with the sarcolemma and helps propagate the action potential into the interior of the muscle fiber?

Accepted Answer

T-tubule

Question 13

A muscle biopsy shows striated, branched fibers with centrally located nuclei and intercalated discs. Which muscle type is this?

Accepted Answer

Cardiac muscle

Question 14

Which of the following best describes the role of the motor end plate in muscle contraction?

Accepted Answer

It contains acetylcholine receptors that initiate depolarization of the muscle fiber

Question 15

Which connective tissue layer surrounds individual muscle fibers?

Accepted Answer

Endomysium

Question 16

A patient is unable to voluntarily move certain muscles, but those muscles still contract during reflexes. Which muscle tissue is most likely affected?

Accepted Answer

Skeletal muscle

Question 17

Which of the following is true regarding the location and function of smooth muscle tissue?

Accepted Answer

It is found in the walls of hollow organs and controls involuntary movements

Question 18

Which of the following equations best represents the relationship between the number of nuclei ($$n) $$and the number of myoblasts ($$m) $$that fuse to form a skeletal muscle fiber?

Accepted Answer

$$n = m$$

Question 19

If the sarcolemma is damaged and becomes permeable to calcium ions, what is the most likely consequence for the muscle fiber?

Accepted Answer

The muscle fiber may undergo continuous, uncontrolled contractions

Question 20

Which of the following best explains why cardiac muscle cells are able to contract in a coordinated fashion?

Accepted Answer

They are connected by intercalated discs that allow electrical coupling

Muscle Tissue & Muscle Fibers: Structure, Types, and Function

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