Q: Which of the following equations correctly represents mechanical advantage in a lever system?

$$\text{Mechanical Advantage} = \frac{\text{Length of Effort Arm}}{\text{Length of Load Arm}}$$

Question 1

During a muscle contraction, which structure moves toward the other: the origin or the insertion?

Accepted Answer

The insertion moves toward the origin.

Question 2

A muscle has its origin on the pubis and its insertion on the xiphoid process. What type of movement does this muscle most likely produce when it contracts?

Accepted Answer

Flexion of the vertebral column

Question 3

The flexor carpi ulnaris attaches to the humerus and the base of the 5th metacarpal. It flexes and adducts the hand at the wrist. Which attachment is the origin?

Accepted Answer

The humerus

Question 4

Which bone is the insertion of the masseter muscle, which is involved in chewing?

Accepted Answer

Mandible

Question 5

Which of the following best describes the role of a fixator muscle?

Accepted Answer

It stabilizes the origin of the agonist.

Question 6

The genioglossus is the primary muscle for sticking out your tongue. The styloglossus pulls the tongue back in. What is the role of the styloglossus in this movement?

Accepted Answer

Antagonist

Question 7

The gastrocnemius and soleus are both located in the posterior calf, while the tibialis anterior is in the anterior lower leg. Which statement is most likely true?

Accepted Answer

The gastrocnemius and the tibialis anterior are antagonists.

Question 8

In a third-class lever, where is the effort applied relative to the fulcrum and the load?

Accepted Answer

Between the fulcrum and the load

Question 9

Most lever systems in the arms and legs are third-class levers. What does this imply about their mechanical properties?

Accepted Answer

They usually work at a mechanical disadvantage.

Question 10

Which fascicle arrangement is best suited for generating a lot of force over a small distance?

Accepted Answer

Multipennate

Question 11

Which muscle name does NOT provide information about the muscle’s action?

Accepted Answer

Transverse abdominis

Question 12

Based on the name, how does the fibularis brevis compare to the fibularis longus?

Accepted Answer

The fibularis brevis muscle is relatively short while the fibularis longus is relatively long.

Question 13

Which of the following best describes a muscle with a circular fascicle arrangement?

Accepted Answer

Circular

Question 14

A muscle with a convergent fascicle arrangement has which of the following characteristics?

Accepted Answer

Origin is wider than insertion

Question 15

If a muscle is named 'biceps femoris,' what does the name indicate?

Accepted Answer

It has two origins and is located in the thigh.

Question 16

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

Accepted Answer

$$	ext{Mechanical Advantage} = \frac{	ext{Length of Effort Arm}}{	ext{Length of Load Arm}}$$

Question 17

A muscle with a bipennate fascicle arrangement is best described as:

Accepted Answer

Fibers extending from both sides of a central tendon

Question 18

Which of the following is an example of a first-class lever in the human body?

Accepted Answer

Extension of the head at the neck

Question 19

Which muscle action term describes a muscle that opposes the action of the prime mover?

Accepted Answer

Antagonist

Question 20

Which of the following best explains why multipennate muscles generate more force than parallel muscles?

Accepted Answer

They have more muscle fibers packed into a given area.

Muscular System: Origins, Insertions, Actions, Levers, and Naming

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