$$MA = \frac{\text{Effort Arm}}{\text{Load Arm}}$$

Question 1

Which of the following best describes the role of a synergist muscle during abduction of the arm?

Accepted Answer

It assists the prime mover by stabilizing the joint or adding extra force.

Question 2

A muscle that causes a specific movement, such as the deltoid in abduction of the arm, is known as:

Accepted Answer

Agonist

Question 3

Which statement about muscle actions is correct?

Accepted Answer

Muscles can only pull, never push.

Question 4

In a lever system, which component is defined as the rigid bar that moves on a fixed point?

Accepted Answer

Lever

Question 5

If the effort is applied farther from the fulcrum than the load, the lever operates at:

Accepted Answer

Mechanical advantage

Question 6

Which equation correctly represents the relationship for mechanical advantage in a lever system?

Accepted Answer

$$MA = \frac{	ext{Effort Arm}}{	ext{Load Arm}}$$

Question 7

A second-class lever in the human body is exemplified by which of the following?

Accepted Answer

Standing on tiptoe using the Achilles tendon

Question 8

Which muscle acts as an antagonist during abduction of the arm?

Accepted Answer

Teres major

Question 9

When naming a muscle, which criterion is used if the name includes 'triceps'?

Accepted Answer

Number of origins

Question 10

Which of the following is true regarding the origin and insertion of a muscle?

Accepted Answer

The origin is attached to a relatively immovable part, and the insertion to a movable part.

Question 11

Which class of lever is represented when the fulcrum is between the effort and the load, such as in nodding the head?

Accepted Answer

First-class lever

Question 12

A third-class lever in the human body is best exemplified by:

Accepted Answer

Flexing the elbow joint

Question 13

Which muscle naming criterion is used in 'sternocleidomastoid'?

Accepted Answer

Location of attachment

Question 14

Which of the following statements about muscle-lever systems is correct?

Accepted Answer

Third-class levers favor speed and range of motion over strength.

Question 15

Which muscle fiber arrangement would you expect in a muscle named 'rectus abdominis'?

Accepted Answer

Fibers running parallel to the midline

Question 16

Which of the following is a correct statement about intramuscular injections?

Accepted Answer

Injected substances cannot survive the oral route due to digestive breakdown.

Question 17

If a muscle is named 'extensor carpi radialis longus', which criteria are combined in its name?

Accepted Answer

Action, location, and size

Question 18

Which of the following is NOT a criterion used in naming skeletal muscles?

Accepted Answer

Type of nerve supply

Question 19

A muscle named 'oblique' would have fibers oriented:

Accepted Answer

At an angle to the midline

Question 20

Which of the following best explains why muscles can only pull and not push?

Accepted Answer

Muscle contraction shortens the muscle, pulling on the attachment points.

Muscular System: Muscle Actions, Lever Systems, and Muscle Naming in Anatomy & Physiology

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