Understanding Why Bones are Called Passive Motion Devices in the Human Motion System

Illustration of why bones are called passive motion tools (freepik)

YOGYAKARTA - Why bones are called passive means of movement is often a question in biology lessons, especially when discussing the human movement system and the role of bones and muscles.

Understanding this concept is important because it is related to the way the body moves, the cooperation between bones, muscles, and joints in human daily activities. To understand it, VOI summarized from the britannica page, the following are some that must be understood first:

Motion Systems in Humans

The human motion system consists of three main components, namely bones, muscles, and joints. Bones form the body's skeleton which serves as a support and protection for vital organs.

Then there are joints that connect between bones and allow movement to occur, while the muscles function to produce a force of motion.

These three components work together. Without any of them, body movement cannot occur perfectly. However, of the three, only muscles have the ability to actively contract and relax.

Active Motion Devices and Passive Motion Devices

Active motion is a body part that is capable of producing its own movement through contraction. In the human motion system, the muscle is an active motion tool because it can shorten and lengthen to move the bones.

On the other hand, passive movement tools are body parts that cannot move on their own. Bones are called passive movement tools because they do not have the ability to contract.

In addition, the bone will only move if there is a force acting on it, especially the pulling force from the muscle.

Why are Bones Called Passive Locomotion?

Bones are not able to produce energy or movement on their own. Bone movement is entirely dependent on the work of the muscles attached to it through tendons. When the muscles contract, the bone is pulled so that movement occurs at the joint.

In addition, bones serve as levers or levers. Then the muscles provide force, the joints become fulcrum points, and the bones become the parts that are moved.

Thus, without muscle contraction, the bones will remain in their original position even though they are connected by a flexible joint.

Read also the article The Process of Forming Human Bones from Content to Adults

The Role of the Joints in Supporting the Bone Movement

A joint itself is where two or more bones meet. Some joints allow movement in one direction, such as the hinge joint in the elbow, while other joints allow movement in multiple directions, such as the ball and socket joint in the shoulder and pelvis.

Although the joints allow for flexibility and diverse directions of movement, the joints do not produce movement. The role of the joint is only as a connector and a giver of space for the bones that are moved by the muscles.

In addition to playing a role in movement, bones also have other functions, such as protecting vital organs, giving the body shape, and being the place where muscles attach. Bones also play a role in the formation of blood cells and the storage of minerals such as calcium and phosphorus.

These functions show that despite being passive in movement, bones still have a very vital role for the human body.

Why bones are called passive means of movement can be explained because bones are not able to move or contract themselves. Bones only serve as supports and levers that are moved by muscles through joints. The point is the cooperation between bones, muscles, and joints allows humans to perform various daily activities well.