Chapter 11, Problem 1CP

Using the terms origin, insertion, and belly, describe how skeletal muscles produce body movements by pulling on bones.

Summary Introduction

To review:

The way in which the skeletal muscles move the body parts, considering the terms belly, insertion, and origin.

Introduction:

The muscle system helps in the movement of body in a uniform manner. The skeletal muscles are the basic components of body, which leads to accurate maintenance of posture. Their function can be controlled in a remarkable manner as they are voluntary muscles.

Explanation of Solution

The bones are connected with each other through tendons and muscles, which work together to bring movement of the body parts. Contraction of the skeletal muscle leads to articulation of the bones, in which one bone remains stationary and the other one moves in an opposite direction.

When muscle tendon gets attached to a stationary bone present in the muscular system, it is called origin. It is generally proximal in position. On the other hand, when muscle tendon gets attached to movable bone, it is called as insertion. It is usually distal in position. The fleshy fragment of muscle present between the tendons is called belly. The figure given below shows the three points of the muscle's tendon attachment on the bones.

Conclusion

Thus, the attachment of the muscle's tendon with the stationary and movable articulating bones is known as origin and insertion, respectively. The middle portion of the connecting muscle is called belly.