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Bones of the Human Body – The Skeletal System and Its Functions

In this article we introduce you to the bones of the human body and explain some if its functions. Bones, in humans, are used for movement, support, protection of the organs, and production of red and white blood cells.

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Our skeletal system is the framework that holds our bodies together. It is made up of all of our bones as well as cartilage and includes our joints.

  • The bones of our skeleton are more or less all of the hard parts in our bodies.
  • They are tough and rigid and are categorized as a connective tissue.
  • The main purpose of bones is to bear weight but they also serve to protect our organs as in the case of the rib cage and skull.

About one third of a bone is organic and the other two thirds are an inorganic compound of calcium salts.

  • The inorganic portion of a bone makes it hard and gives it its rigidity so that it can resist compression and be able to bear weight.
  • The organic part of the bone gives it resiliency and enables the bone to withstand tensile force.
  • Cartilage is another type of connective tissue that is more rubbery than bone.

It serves as a frame work in places where bone would be too hard and, because of its elasticity, it also functions as a shock absorber and provides padding in the joints.

The main difference between bone and cartilage is the number of minerals contained in them. Bone contains a high degree of calcium salts which gives them their hardness while cartilage contains much less enabling it to remain relatively soft and elastic.

The joints of the skeletal system are the places where bones meet and act as a hinge; such as in the elbows and knees.

  • There are some joints which are not designed to allow movement but instead enable the skeleton to expand as we grow.
  • Babies have more joints than adults; this is to enable their bodies to expand and change as they grow.

As they grow into adulthood, these extra joints fuse together reducing the overall number of bones in their bodies.

The bones that meet at a joint are held together by ligaments,

  • tough fibrous bands of connective tissue,
  • and their ends are coated in cartilage that acts as padding enabling the two bones to rub together without wearing down.

In general, the human skeleton can be divided into two main sections: the axial skeleton and the appendicular skeleton.

The axial skeleton is made up of all the bones that form the axis of our bodies; mainly the skull and spine along with the rib cage.

The appendicular skeleton is the bones of our appendages. It is made up of the bones of our arms and legs as well as the pelvis and shoulders including the clavicle and scapular. So you now you know a bit about what the skeletal system is; but what does it actually do?

Skeletal system functions

Each of our skeletons serve a number of functions.

Primarily it gives our bodies shape and provides strength and support.

  • Our bones enable us to stand upright and move around; without them we would be just a mass of soft tissue.
  • Our bones also protect our major organs.
  • The skull is the main line of defence for our brains, and our rib cage protects our heart and lungs. If these organs ore damaged it is usually fatal so from an evolutionary point of view the bones protecting them are essential to our survival.
  • Bones are also an essential part of movement.

Muscles are connected to our bones and where bones meet at a joint the muscles around it contract and expand enabling the two bones to act as a hinge. This is what enables us to walk and use our arms. Without the hard bones to give leverage we wouldn’t have the dexterity that we do.

The larger bones in our bodies are hollow and contain bone marrow which is a fatty connective tissue.

  • Bone marrow produces blood cells as well as lymphocytes which aid our immune systems.
  • Bone marrow is soft and spongy, unlike the hard bone that encases it, and is infused with blood vessels.

When we are born our bones contain red marrow, which is involved in cell production, but as we grow older this starts turning into yellow marrow.

Yellow bone marrow is mostly fat and serves the purpose of providing sustenance as well as keeping the right conditions for the bone to function.

As you can see the skeleton has more than one role in our lives.

The human skeletal system is an amazing and complex part of our bodies that enables us to perform our daily functions and protects our lives. Hopefully with this article you now have a much better idea about what it is and what it does. If your interest has been piqued, I encourage you to look further. The study of the skeletal system is essential to our health and well being and is an important part of understanding the bones of the human body.


skeletal system

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LearnBones.com provides a resource on both the bones of the human skeleton and the Muscular System. Learn about the bones, memorize their names, and see their positions in the human body. To get started, click on one of categories above. If you want more information about this site, check out the About or Contact Us pages.

Test Your Knowledge

How Many Bones in the Human Body?

An adult has a total of 206 bones in their skeleton

How many Bones in a Child's Body?

A newborn baby has 270 bones in the skeletal system. Most of their skeleton is made up of cartilage which forms bone as it hardens over time. The bones in a child's skeleton fuse together as they grow, reducing the number, up until about 25 years old.

What is The Strongest Bone in the Human Body?

The femur or thigh bone is the strongest bone in the body. It is situated between the pelvis and the knee. It is also the longest bone in the body and is fully one quarter of your bodies' height.

What is the Weakest Bone in The Body?

The weakest bones in your body are the tiny bones inside your ear that enable you to hear. On the other hand; the most commonly fractured bone is the clavicle.

What is the Hardest Bone in the Body?

The hardest bone in the body is the petrous portion of the temporal bone. The temporal bones are found at the sides and base of the skull and the petrous portion is specifically the part at the base of the skull that contains the organs for hearing.

Where are the Smallest bones in Your Body Located?

The smallest bone in the body is called the stapes. It is a stirrup shaped bone found inside the ear drum that transmits vibrations enabling us to hear.

How many Bones are in the Leg?

A human leg contains 30 bones. There are 26 bones that make up the foot, and the four major bones of the leg, which are the thigh bone (femur), the shin bone (tibia), the calf bone (fibula) and the knee cap (patella)