Study Material

The hard parts of an animal body present inside or outside the body collectively form the skeletal system.

Skeleton serves as the reservoir of many minerals, like calcium and phosphate.

The marrow of the long bones is the site for the haemopoiesis, i.e., for mation of blood cells 

(RBC, WBC).

 

The skeleton plays a vital role in movement and locomotion.

Human skeleton consists of 206 pieces of bones.

In infants 306 bones are present. The act of moving from place to place is known as locomotion. 

It involves the movement of the whole body, as in walking, running, swimming or flying. Movement 

is the change in position of only a part of the body, as movement of stem towards light in plants. 

 

 

Why animals need locomotion : 

 

1. Locomotion enables animals to move from an unfavourable place or environment to a safe place.

2. It helps them to escape from their enemies and predators.

3. It hepls animals to find their partners for reproduction, and to move to safe place for laying 

eggs or rearing of the young ones.

 

 

 

 

Girdle bones : These provide a connection between the axial skeleton and limbs. The two 

                          girdles are named as pectoral and pelvic girdles, respectively.

 

Joints are the place of articulation between two or more bones or between a bone and a cartilage.

Due to the presence of a number of joints, the movement of the different body parts and the whole body is possible.

 

 

(i) Fixed or immovable or fibrous joint : There is no space between the bones. The attached bones are tightly held with the help of while fibrous connective tissure

                                                                      e.g. Between bones of vertebrae and pelvic girdle.

 

(ii) Slightly movable or cartilaginous joint : It is an articulation between the bones that allows very little movement e.g. Between bones of vertebrae and pelvic girdle.

 

(iii) Movable joint or synovial joint : It is a joint which allows the movement of articulating bones such that they can move extensively upon each other. The spa
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