$$Effort \times Effort\ Arm = Load \times Load\ Arm$$

Question 1

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

Accepted Answer

It is the plasma membrane of the muscle fiber, responsible for conducting electrical impulses.

Question 2

A patient is unable to flex their forearm at the elbow. Which muscle is most likely impaired?

Accepted Answer

Biceps brachii

Question 3

Which of the following statements about muscle contraction is correct?

Accepted Answer

Muscle contraction occurs when myosin heads bind to actin, forming cross bridges.

Question 4

Which lever system is exemplified by standing on tiptoe, where the ball of the foot acts as the fulcrum?

Accepted Answer

Second-class lever

Question 5

Which muscle arrangement allows for the greatest range of motion but the least power?

Accepted Answer

Parallel

Question 6

During isometric contraction, which of the following occurs?

Accepted Answer

Muscle tension increases but the muscle does not shorten.

Question 7

Which of the following is the correct sequence of events in the cross-bridge cycle?

Accepted Answer

Cross bridge formation → Power stroke → Cross bridge detachment → Cocking of myosin head

Question 8

Which muscle is the prime mover for flexion at the hip joint?

Accepted Answer

Iliopsoas

Question 9

A muscle with fascicles arranged obliquely to a central tendon, resembling a feather, is classified as:

Accepted Answer

Pennate

Question 10

Which of the following best explains why bipennate and multipennate muscles are more powerful than parallel muscles?

Accepted Answer

They contain more muscle fibers packed into a given muscle length.

Question 11

Which of the following equations correctly represents the relationship in a lever system?

Accepted Answer

$$Effort 	imes Effort\ Arm = Load 	imes Load\ Arm$$

Question 12

Which muscle is responsible for the primary movement of the diaphragm during inspiration?

Accepted Answer

Diaphragm

Question 13

Which of the following muscles is NOT part of the rotator cuff?

Accepted Answer

Teres major

Question 14

A patient presents with difficulty abducting their arm at the shoulder. Which muscle is most likely affected?

Accepted Answer

Deltoid

Question 15

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

Accepted Answer

It stores and releases calcium ions necessary for contraction.

Question 16

Which of the following muscles is innervated by cranial nerve VII and is responsible for facial expression?

Accepted Answer

Orbicularis oculi

Question 17

Which of the following is a function of the muscles of the abdominal wall?

Accepted Answer

Lateral flexion and rotation of the trunk

Question 18

Which of the following muscles is a primary extensor of the knee?

Accepted Answer

Quadriceps femoris

Question 19

Which of the following muscles is responsible for dorsiflexion of the ankle?

Accepted Answer

Tibialis anterior

Question 20

Which of the following best describes the role of ATP in muscle contraction?

Accepted Answer

ATP is required for the detachment of myosin heads from actin after the power stroke.

The Muscular System: Structure, Function, and Organization

Study Guide - Practice Questions