Movements In The Body

The type of movement where an organism can change its place is known as locomotion

• It forms the framework of our body, provides shape and support , and holds the body upright • It helps in the movement of various parts of our body • It protects the internal organs of our body. The skull protects the brain, ribs protect the heart and the lungs, and so on • Bones are filled with a spongy mass called bone marrow where blood cells are formed.

The skull protects our brain.It also has holes for the eyes, nose and ears. There are a total of 22 bones present in the skull. Out of these, 14 form the face and the jaw. Rest of the eight bones are pesent in the upper head region and are fixed joints

The backbone is a central supporting rod for the skeleton, consisting of 33 vertebrae. It runs from the skull to the lower back. The vertebrae are joined to each other, allowing us to bend and twist. The spinal cord passes through each vertebra’s hole. All animals with a vertebral column are vertebrates.

Ribs are curved, flat and thin. There are 12 paris of ribs that is a total of 24 ribs. These are joined to the backbone at the back and the breast bone at the front. The last two pairs of ribs are not attached in front and are called floating ribs. The ribcage protects the heart and the lungs as well as parts of the stomach and kidneys.

Limbs allow us to perform various types of movement. We have two pairs of limbs-the fore limbs (arms) and the hind limbs (legs). Almost half our bones are found in the limbs. The long bone in the upper arm is called humerus. The two bones in the lower arm are called radius and ulna. The humerus is attached to the vertebral colomn by the collar bone and the shoulder blade. The longest bone in our body is the femur, present in the thigh. The two bones in the lower legs are called tibia and fibula.The pelvis that supports the legs is attached to to lower end of the backbone.

A joint is the place at which two bones meet and are joined together. Joints make our body flexible. At a joint, the two bones are held together by strong and elastic bands called ligaments. The part of a bone that joins with another bone is covered with cartilage. Cartilage is a tissue that prevents bones from rubbing against each other. Our body parts can move only at the joints, but not all joints allow movement. Based on the extent to which the joints allow movement, they are divided into three categories-fixed, slightly movable and freely movable joints.

• Immovable joints do not allow movement. • Slightly movable joints allow only bending and rotation.The joints present between the vertebrae are an example of slightly movable joints. • Freely movable joints allow movement in all directions. There are four types freely movable joints-hinge joint, ball and socket joint, pivot joint and gliding joint.

A ball and socket joint is the joint in which the ball shaped end of one bone fits into the hollow cavity of the other bone.This type of joint allows movement in all directions-forwards and backwards as well as side to side. The joint between the humerus and sholder blade and the joint between the femur and the hip bone are examples of ball and socket joint

The joints present in our elbow and our knee are hinge joints. They allow movement in only two directions, forward and backward, or upward and downward. Hinge joints in our body also allow some rotation. The finger joints, the knee joints and the elbow joints are examples of hinge joints

In the pivot joint, the end of one bone is in the form of a cylinder. The end of the other bone is in the form of a ring. The cylinder fits into the ring and rotates inside it, or the ring rotates around the cylinder.

The gliding joint allows banes to glide over each other and provide slight movement. These bones have flat ends and can move from side to side as well as back and forth. The joints at the ankle and the wrist as well as the joints between the vertebrae are examples of gliding joints.

The bones in our head that protect our brain are joined togethers by fixed joints. They cannot move. Similarly, the upper jaw and the rest of the head are joined by a fixed joint.

Bones cannot move by themselves. It is the muscles that make the bones move and help in body movement. Muscles are attached to bones by tissues called tendons. Muscles work in pair to produce movement because muscles can only pull, not push. The muscle called flexor contracts to bend a joint. When it relaxes, the other muscle called extensor contracts to straighten the same joint.

It is possible to see the image of bones in a living being using radiation known as x-rays. X-rays are special rays that can pass pass through the soft tissues but not through the bones. Hence, an image is created that reveals the nature of the bone . Bones are seen as a white shapes against a black background. X-rays are also used to detect cracks in metals and at airports for luggage inspection.