The Skeletal System

Many unicellular organisms cannot move on their own. Instead, they are transported by air, water or other organisms. Although there are some unicellular organisms that have adapted to move independently. For example, some bacteria have one or multiple flagella that allow them to move. Movement is essential for many multicellular organisms to function and survive.

A bone is a living tissue composed of cells that work together to perform specific functions. There are 206 bones in the adult human skeleton, which provide structure and support to the body, protect vital organs, and enable movement. When a bone is broken, it has the ability to repair itself.

  • Calcium and other minerals make bones strong, healthy and more flexible

Below, you can see some of the major bones in the body.

 detailed illustration of a human skeletal system, viewed from both the front and back perspectives. Various bones are labelled with lines pointing to the respective bones. Some of the identified bones include the skull, mandible, cervical vertebrae, clavicle, scapula, humerus, sternum, ribs, ulna, radius, thoracic vertebrae, lumbar vertebrae, ilium, sacrum, ischium, femur, patella, tibia and fibula. The illustration provides a comprehensive overview of the major bones in the human body.

Functions of the Skeleton

An illustration of a human skeletal system, surrounded by close-up diagrams detailing the various functions of bones. From the top left, there's an illustration of a bone marrow with red blood cells, labelled "Produce Blood Cells". Moving to the right, there's a depiction of the skull encasing the brain, labelled "Protects Internal Organs". Below this, there's an illustration of a bone releasing minerals, labelled "Stores and Releases Minerals". Further to the bottom left, there's a depiction of a bone storing fat cells, labelled "Stores and Releases Fat". Moving right, there's an image of the lower leg and foot bones, labelled "Supports the Body". Finally, on the bottom right, there's an illustration of a joint showing its movement, labelled "Facilitates Movement".

There are four primary functions of the skeleton:

  • Supporting the body
  • Protection of vital organs
  • Producing blood cells
  • Facilitating movement


The skeleton provides support to the body. Without it, we wouldn’t be able to maintain an upright posture.


The skeleton protects our major organs.

For example:

  • The skull protects our brain
  • The backbone protects our spinal cord
  • The rib cage protects our heart and lungs

Making blood cells

There are different kinds of blood cells:

  • Red blood cells – Carry oxygen throughout the body
  • White blood cells – Destroy harmful microorganisms in the body

Bone marrow is a soft, spongy tissue that produces red and white blood cells. Healthy bone marrow is important in the body and is located at the centre of certain large bones.


Bones play an important role in body movement, allowing the body to move as a whole or its individual parts. This is because they transmit the force from muscle contractions.

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