6th Class Science Body Movement Movement

Movement

Category : 6th Class

Movement

Most animals can move from one place to another. This type of movement is called locomotion. Animals move from place to place in search of food, in response to the environment, to escape from enemies and in search of mates. However, when we speak about movement, in humans, we do not mean only locomotion, for which we use our legs. We also mean other kinds of movement, like bending, sitting, stretching, turning, and so on. What makes movement possible are the joints. If our skeleton were made of one bone, we would not be able to move. Imagine the arm without the joint at the elbow. You would not be able to bend it, which would make even the simple task of putting food into your mouth impossible.

The ligaments, which bind bones, make it possible for them to move by stretching and relaxing. The cartilage cushioning bones and the synovial fluid, which lubricates joints, help in the movement of the bones. But what actually makes bones move is the contraction and relaxation of the muscles attached to the bones. Every bone capable of movement has muscles attached to it by tough, elastic cord like tissue called tendon. When a muscles attached to a bone contracts, it pulls the bone and makes it move. But it cannot push it back.

So another muscle is required to pull it back in the opposite direction. That is why muscles work in antagonistic pairs.

One muscles pulls a bone away from the joint, while its partner pulls it back. The biceps and triceps in the upper arm are an example of such an antagonistic pair of muscles. The contraction of the biceps pulls the forearm up, while the contraction of the triceps pulls it back down.