Question 1

Which structure in a skeletal muscle fiber is responsible for storing and releasing calcium ions during muscle contraction?

Accepted Answer

Sarcoplasmic reticulum (SR)

Question 2

What is the primary function of the transverse (T) tubules in skeletal muscle fibers?

Accepted Answer

To allow electrical impulses to travel deep into the muscle fiber

Question 3

Which protein forms the thick myofilaments in skeletal muscle fibers?

Accepted Answer

Myosin

Question 4

What is the functional unit of muscle contraction in skeletal muscle?

Accepted Answer

Sarcomere

Question 5

Which of the following best describes the role of acetylcholine (ACh) at the neuromuscular junction?

Accepted Answer

It acts as a neurotransmitter to initiate an action potential in the muscle fiber

Question 6

During muscle contraction, what event directly follows the binding of calcium to regulatory proteins on the actin filament?

Accepted Answer

Myosin heads attach to actin, forming cross-bridges

Question 7

Which property of skeletal muscle allows it to return to its original length after being stretched?

Accepted Answer

Elasticity

Question 8

A single motor neuron and all the muscle fibers it stimulates is called a:

Accepted Answer

Motor unit

Question 9

Which enzyme is responsible for breaking down acetylcholine in the synaptic cleft, thereby ending muscle contraction?

Accepted Answer

Acetylcholinesterase

Question 10

What is the correct sequence of events at the neuromuscular junction leading to muscle contraction?

Accepted Answer

Nerve impulse → Calcium influx into axon terminal → ACh release → ACh binds sarcolemma receptors

Question 11

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

Accepted Answer

They are formed by the fusion of multiple precursor cells during development

Question 12

Which of the following movements describes decreasing the angle between two bones at a joint?

Accepted Answer

Flexion

Question 13

If a muscle acts as a prime mover, what is its main function?

Accepted Answer

To produce the major force for a specific movement

Question 14

Which muscle is primarily responsible for abducting the arm?

Accepted Answer

Deltoid

Question 15

What is the role of ATP in the sliding filament theory of muscle contraction?

Accepted Answer

It provides energy for myosin heads to detach and recock for another power stroke

Question 16

Which of the following best describes the insertion of a muscle?

Accepted Answer

The attachment to a movable bone

Question 17

A patient is unable to extend their elbow after an injury. Which muscle is most likely damaged?

Accepted Answer

Triceps brachii

Question 18

Which property of muscle tissue is defined as the ability to receive and respond to a stimulus?

Accepted Answer

Irritability (responsiveness)

Question 19

Which of the following is true regarding the arrangement of actin and myosin in skeletal muscle?

Accepted Answer

It creates the striated appearance of skeletal muscle

Question 20

Which muscle is responsible for flexing the vertebral column?

Accepted Answer

Rectus abdominis

Microscopic and Functional Anatomy of Skeletal Muscle Fibers

Study Guide - Practice Questions