BODY MOVEMENT

There are so many movements that happen in our bodies.Observe the movements in your body as you breathe. You must be blinking your eyes, time to time.  Different parts of your body move while you remain at the same place, in these examples. You also move from one place to another — you get up and go to your teacher or to the school compound, or go home after school. You walk, run, skip, jump and move from place to place.

How do animals move from place to place?

Walk, run, fly, jump, creep, crawl, slither and swim – these are only a few of the ways in which animals move from one place to another. 

Why are there so many differences in the way that animals move from place to place?
Why is it that many animals walk while a snake slithers or crawls and a fish swims?

Plant do not move from place to place, but, do they show any other kind of movements?

We will try to get answer of these question in coming sections.

Human Body And Its Movements

Why is it that we are able to move a few parts of our body easily in various directions and some only in one direction? Why are we unable to move some parts at all?

We can bend or rotate our body in places where two parts of our body seem to be joined together — like elbow, shoulder or neck.  These places are called joints. 

 If our body has no joints, do you think it would be possible for us to move in any way at all?

Bones have hard structure. Bones cannot be bent. So, how do we bend our elbow? Actually, It is not one long bone from the upper arm to our wrist. It is different bones joined together at elbow. Similarly, there are many bones present in each part of the body. We can bend or move our body only at those points where bones meet. 

There are different types of joints in our body to help us carry out different movements and activities.

1. Ball and socket joints :The bowl is like the part of the shoulder to which our arm is joined. The rounded end of one bone fits into the cavity (hollow space) of the other bone. Such a joint allows movements  in all directions.

2. Pivotal Joint: The joint where our neck joins the head is a pivotal joint. It allows us to bend our head forward and backward and turn the head to our right or left.In a pivotal joint a cylindrical bone rotates in a ring.

3. Hinge joints: Open and close a door a few times. Observe the hinges of the door carefully. They allow the door to move back and forth. Similarly, The elbow has a hinge joint that allows only a back and forth movement.

4. Fixed joints : There are some bones in our head that are joined together at some joints. The bones cannot move at these joints. Such joints are called fixed joints.There is a joint between the upper jaw and the rest of the head which is a fixed joint.

All the bones in our body also form a framework to give a shape to our body. This framework is called the skeleton.  Bones and cartilage form the skeleton of the human body. It gives the frame and shape to the body and helps in movement. It protects the inner organs.

Human Skeleton

How do we know the shapes of the different bones in our body? 

We can have some idea about the shape and number of bones in some parts of our body by feeling them. One way we could know this shape better would be to look at X-ray images of the human body. The X-rays show the shapes of the bones in our bodies.

Some Important Bones 

• The ribs (bones of chest) are curiously bent. They join the chest bone and the backbone together to form a box. This is called the rib cage. Some important internal parts of our body lie protected inside this cage.
• Backbone is made of many small bones. The rib cage is joined to these bones.
• Make your friend stand with his hands pressed to a wall. Ask him to and try to push the wall. Do you see two bones standing where his shoulders are? They are called shoulder bones. 
• Pelvic bones enclose the portion of your body below the stomach. This is the part you sit on. 
• The skull is made of many bones joined together. It encloses and protects a very important part of the body, the brain. 

Cartilage

Some additional parts of the skeleton hat are not as hard as the bones and which can be bent. These are called cartilage. 

Feel your ear. Do you find any hard bony parts that can be bent? There do not seem to be any bones here, isn’t it?  Do you notice anything different between the ear lobe and the portions above it as you press them between your fingers? You do feel something in the upper parts of the ear that is not as soft as the ear lobe but, not as hard as a bone, isn’t it? This is cartilage. Cartilage is also found in the joints of the body. 

We have seen that our skeleton is made up of many bones, joints and cartilage.

Muscles:

The muscle bulged due to contraction (it became smaller in length). When contracted, the muscle becomes shorter, stiffer and thicker. It pulls the bone.

Muscles work in pairs. When one of them contracts, the bone is pulled in that direction. The other muscle of the pair relaxes. To move the bone in the opposite direction, the relaxed musle contracts to pull the bone towards its original position, while the first relaxes. A muscle can only pull. It cannot push. Thus, two muscles have to work together to move a bone.

Are muscles and bones always required for movement? How do other animals move? Do all animals have bones? What about an earthworm or a snail?

We will study this here , "Gait Of Animals".
Check out our Quiz section on "Body Movement".