• The framework of bones in our body is called the skeleton.
• The skeleton gives shape and support to our body and also it protects the inner organs like brain, heart, lungs etc.
• A newly born child has about 350 bones in its body but an adult has just 206 bones.
• Our skull is made up of 8 flat bones and the face is made up of 14 facial bones.
• The skull protects the brain.
• The facial bone protects eyes, nose and tongue.
• The backbone is also known as the vertebral column.
• The vertebral column is made up of 31 small bones called vertebra.
• The vertebral column protects the delicate spinal cord.
• The rib cage protects the lungs and the heart.
• The rib cage is made up of 12 pairs of long curved bones called the ribs.
• The ribs joint to the back with the backbone whereas in the front only 10 pairs joint to the breast bone.
• Two pairs of the ribs do not join the breast bone and are known as floating ribs.
  

  

• The upper arm has a single bone called the humerus, whereas the lower arm has two bones.
• In the upper leg is the femur, which is the longest bone of the human body and it supports the weight of the body.
• The lower half of the leg has the shinbone and the calf bone. 
• The point where two separate bones meet is called a joint.
• Joints enable us to move and bend.
• Two bones are joined to one another with the help of ligaments.
• There are four main types of joints.
  • Hinge Joint
    • It is present in the knees, elbows, toes and fingers.
    • It allows movement in only one direction. 
  • Ball and Socket Joint
    • In this type of joint one of the bones forms the round ball part which fits into the hollow part of another bone called the socket.
    • It is present in between the humerus and shoulder and in between the femur and the hip bone.
    • It allows movement in all directions.
  • Gliding Joint
    • In these two bones can slide over one another.
    • This joint is present in wrist and ankles.
    • It allows side to side as well as backward and forward movement.
  • Pivot Joint
    • It is present in our neck and between the vertebra.
    • The rounded end of one bone twists around in a hole in the other.

Muscles

• Muscles help the bones to move.
• Muscles are made of tough elastic tissue.
• Muscles are attached to the bones by strong fibres called tendons.
• The muscles which are in our control are called voluntary or skeletal muscles.
• The muscles which are not in our control are called involuntary or smooth muscles.
• Involuntary or smooth muscles work on their own.
• Involuntary muscles are found in the food pipe, stomach, intestine etc.
• The muscles of our heart are called cardiac muscles.
• Cardiac muscles are also involuntary muscles.
• There are about 640 muscles in our body.