Title Chapter 5 Body Movements.pdf ✅

SCIENCE CHAPTER 5: BODY MOVEMENTS
(2) 05 BODY MOVEMENTS Body Movements Introduction • The ability of moving one’s body from one place to another is called locomotion. • In nature, the primary reason for movement has been the search of food and shelter, or in saving oneself from harsh climatic conditions or for escaping from being hunted. Human Skeleton • All bones in the body form a framework which gives shape to the body. This bony framework inside the body is called the skeleton. • There are 206 bones in an adult human skeleton. • Some additional parts of the skeleton are not as hard as bones and can be bent. They are called cartilages. Functions of Skeleton • It holds the whole body together and gives itshape. • It protects many delicate organs of the body from outside damage. • It provides numerous points for attachment of the muscles of the body. • It helps in the movement of body parts and locomotion.
(3) 05 BODY MOVEMENTS • The human skeleton consists of a strong backbone which has a skull at its top end. • The skull is made of many bones joined together. It encloses and protects the most important part of the body, i.e. the brain. • Ribs are attached to the upper part of the backbone forming a ribcage. • The breastbone also known as the sternum is present in front of the ribcage. • Ribcage protects the heart and the lungs. Muscle Movements • The muscle is a fibrous tissue in the body which has the ability to contract when required. • On contraction, muscles become shorter, stiffer and thicker because they pull the bones. • Muscles always work in pairs. When one muscle contracts, the bone is pulled in that direction and the other muscle relaxes. • To move the bone in the opposite direction, the relaxed muscle contracts and brings the bone to its original position, while the first relaxes. A muscle cannot push. It can
(4) 05 BODY MOVEMENTS only pull. Human Body and its Movement • The point where two or more bones meet in the body is called a joint. • Bones do not move. It is the joint which helps in movement. Type of Joint Features 1. Ball and Socket Joint • The spherical or hemispherical head of one bone fits exactly into a corresponding hollow or socket of the other bone. • Examples: Shoulder and hip joints