The Skeletal System

The skeletal system has the job to help protect the body and to help the body to move.

In the human skeleton, there are 206 bones. Humans are vertebrates and being a vertebrate means that we have bones that are located on the inside of the body and this is called an endoskeleton.

Support and Protection

Our body is supported by all of our bones that allow us to stand and to sit. The limbs and joints in our body help the bones to be able to move.

The skeleton helps to protect our organs such as our brain, heart and lungs, and other organs.

Skeletal Storage

The skeleton also helps to store calcium and hematopoiesis, which is how the blood produces cellular components such as proteins, plasma, and other cells such as white blood cells, red blood cells, and platelets.

White and red blood cells and platelets are found inside of the bone, and this is part of the bone marrow.

Axial and Appendicular Skeleton

There are two parts of the skeleton, the axial skeleton, and the appendicular skeleton.

The axial skeleton includes the skull and the ribcage and the vertebra column. This is the center of our body.

The pelvis forms the appendicular skeleton which is attached to the axial skeleton. Flat bones are bones that make up the skull, the ribs, and the pelvis.

Flat Bones

These bones are called flat bones because they describe their shape.

The flat bones have a spongy or cancellous bone which and the outer shell or the compact bone.

Flat bones help to protect the organs and help to protect the bone marrow.

Long Bones

Long bones are the humerus, the femur, and other bones. The long, middle portion of the long bone is called the diathesis and the end of the long bone is called the epiphysis and the small area between the two is called the metathesis.

The metathesis is also called the growth plate. The growth plate allows people to continue to grow until the growth plate closes.

The long bones are also made up of spongy bones and a compact bone. These bones are used for movement and to frame the body in shape.

Bone Marrow

There are two different types of bone marrow, red bone marrow, and yellow bone marrow. The red bone marrow has the main function of making red blood cells.

The yellow bone marrow is used to store fat cells. Yellow bone marrow is found in long bones.

Skeletal System Facts

  • Endo means within or inner in Greek.
  • The skeletal system is made up of bone and cartilage.
  • The cartilage is mostly found between bones.
  • The skull has the cranium which is the strongest bone.
  • The skull, cranial and facial bones do not move except for the jaw bone.
  • The facial skulls help to protect the eyes.
  • The backbone is called the vertebral column. This is made up of vertebrae which are hollow and joined together.
  • The spinal cord runs in the center of the vertebrae.
  • The sternum helps to form the rib cage.
  • The rib cage helps protect the heart and the lungs.
  • The clavicle and scapula help to form the shoulder. This gives shape and helps with movement.
  • Each finger has three bones, but the thumb only has two bones.
  • A joint is a place where two or more bones join together.
  • Fixed joint means that the bones are not moveable. An example of a fixed joint is the skull bone.

What Did You Learn?

  • How many bones are in the adult skeleton? There are 206 bones in the adult skeletal system. There are 300 bones in a baby’s skeleton.
  • What kind of movement do our bones help us to do? Our bones help us to sit and stand.
  • What are the two parts of the skeleton? The two parts of the skeleton are appendicular and the axial.
  • What are the two types of bone marrow that the body has? The two types of bone marrow are the red blood marrow and the yellow blood marrow.
  • Which blood marrow makes red blood cells? The red blood marrow makes red blood cells. The red blood marrow is red because of the red blood cells that it produces.
  • What are the main functions of the skeletal system? The main functions of the skeletal system is to protect our bodies and to help us to move.