Rib Cage
If we take a deep breath, hold it for a while and move our hand on the chest, we will find a number of bones in the chest region. These chest bones are called ribs. Ribs are the curved bones in our chest (see Figure 4). Ribs exist in pairs. There are 12 pairs of ribs in the chest of our body. We know that there is a long backbone at the back of our body. There is also a small bone called breast bone in the chest region, in front of our body (see Figure 4). One end of all the ribs is joined to the backbone and their other end is joined to the breast bone. In this way, all the rib bones, -Eye soo a part of backbone, and the breast bone, join to form a 'bony cage" or box-like structure'. The hollow, bony structure formed by the ribs is called 'rib cage' (see Figure 4). Some of the important internal organs of our body such as heart, lungs and liver lie inside the strong, bony rib cage. The rib cage protects the delicate internal organs like heart, lungs and liver. The rib cage also takes part in our breathing movements. We will study this in detail in higher classes. From the above discussion we conclude that the main functions of the rib cage are the following:
(1) Rib cage protects the internal organs of the body such as heart, lungs and liver. 2. Rib cage takes part in our breathing movements.
Skull
The bony part of our head is called skull (see Figure 2). It is called 'khopri or 'kapal' in Hindi. The skull is made of 22 bony plates joined together. Our brain is inside the skull in its upper part. The brain is made of soft tissue which could be easily damaged without a hard covering. The bones of skull form a strong case around the brain. In this way, skull protects the brain. The lower part of skull contains the face bones (including nose bone). Our face has sense organs such as eyes, ears and nose. The skull also protects the main sense organs like eyes, ears and nose. The eyes are contained in two large cavities called 'eye sockets' in front of the skull (see Figure 2). From this discussion we conclude that some of the main functions of the skull are as follows:
(i) Skull protects the brain.
(ii) Skull protects the sense organs of the face (like eyes, ears and nose). (iii) Skull gives shape to our head.