Category :
5th Class
Human body (Nervous system bones and muscles)
Tit bits
The longest and strongest bone in the body is the thigh bone (femur).Its length is about a quarter of your height. It can take a load along the bone of over a tonne, but sideways blow can break it much more easily.
- The bones and joints in our body form the skeletal system while various muscles form the
Muscular system. Together these systems help us to move and perform various movements,
- The skeleton gives shape and support to our body. It consists of the skull, backbone, ribcage, bones of arms and legs, and the girdles.
- The backbone is not a single bone. It is about a quarter of your height. It can made up of 33 small bones called Backbone is also called the vertebral column. It protects the spinal cord.
- The rib cage is made up of 12 pairs of long, thin curved bones called ribs which protect the lungs and the heart. Our skull protects the brain and supports the head. The shoulders are supported by girdles. There are long bones in the arms and the legs. The whole skeletal system is composed of 206 bones.
- Bones are light but very strong. To remain strong and healthy, bones require vitamin D, calcium and
- The place where two bones meet is called a joint. Joints can be movable or Except the lower jaw, all the other bones of the skull are immovable. Movable joints work in different ways to enable a wide variety of movements.
- The hinge joint works like the hinge of a door. The knee joint and the joint of the forearm are examples of hinge joints.
- The ball and socket joint in our shoulders enables us to rotate our arm in a full circle. The ball like head of the upper arm bone fits into the cup-like socket of the shoulder bone.
- The pivot joint in the neck helps you move your head from side to side. The sliding Joint in the wrist helps the bones to slide over each other.
- Muscles, by contracting and relaxing, help the bones to move. Most of the muscles Work in pairs. When one set of muscles contract, the antagonistic muscles expand and vice – versa.
- The movements which are in our control are called voluntary movements. The muscles which help in voluntary movements are called voluntary muscles. The facial muscles, the muscles of the arms and the legs, the muscles in our hands and feet are some voluntary muscles.
- The movements which are not under our control are called involuntary movements. The muscles which enable involuntary movements are called involuntary muscles. The muscles of the heart, lungs, intestines, and the blood vessels are examples of some involuntary muscles.
- The nervous system consists of the brain, the spinal cord and the network of nerves.
- Brain is the controlling center of all activities that take place in your body It Receives messages from all parts of the body and sends instructions to muscles and glands.
- The brain consists of the cerebrum, cerebellum and medulla each part performs a different function.
- There are three kinds of nerves - sensory nerves, motor nerves and mixed nerves.
- Reflex actions are automatic reactions of the body that do not need thinking they are controlled by the spinal cord. Our sense organs - eyes, ears, nose, tongue and skin - give us information about our
