The Bone Structure

joeldgreat By joeldgreat, 24th Nov 2010 | Follow this author | RSS Feed | Short URL http://nut.bz/1l9p8x_a/
Posted in Wikinut>Guides>Science>Biology>Human Biology

Knowing the different materials, what bones are made of and how bones are connected.

Introduction

Bones make up of about 12 percent of our body’s mass. If your body mass is 42 kilogram, your bones would be a little 5 kilograms. But with this, bone is as strong as steel as and stronger than the same amount of concrete. We can feel our bones but we cannot see them. For children, if you see the bones of a chicken, pig or a cow, then you will have an idea of how the bones in your body look.

Layers of bone materials

Bone material consists of several layers. The surface of a bone is covered with a thin membrane called periosteum. Beneath the periosteum is a hard, compact bone, inside this hard bone is a spongy bone. Inside the spongy bone is the bone marrow, where red and white blood cells are produced.

What Bones are made of

Bones contain minerals such as calcium, phosphorus and potassium. These minerals make the bones hard and rigid. Bones also contain a fiber-like protein called collagen. Collagen makes bones tough so that they can withstand stress and strain. Like other body tissues, bones are alive. Bones grow. But although they get bigger, their shape remains the same. If you happen to break a bone, the bone can repair itself. But it is also important for children to inform your elders right away so that you will get proper medical attention.

How bones are joined

The point where two bones meet is called joint. Some joints do not allow bones to move. There are joints which allow limited movement and there are joints which allow different kinds of movements. The cranium which protects the brain consists of eight fairly flat bones. The joints between these bones are firmly secured by fibrous tissues. Thus, the bones cannot move. These joints are called fixed joints. Fixed joints, or sutures, do not allow any movement. Turn your head to the left, then to the right. You can do this because of the pivot joint at the point where a bone of the head meets the neck bone. A pivot joint allows limited movement only.

Now, try to bend, then straighten your fingers. Bending and straightening are movements made by hinge joints. You can also bend and straighten your arms and legs. Aside from these, you can also rotate them. The knee and elbow are modified hinge joints. Move your arms sideward, forward, backward and around. You can do these because of the ball-and-socket joint where your upper arm bone meets your shoulder bone. The rounded end of your upper arm bone fits into a hollow or socket at the end of your shoulder bone. The joints between vertebrae are called gliding joints. Gliding joints enable the vertebra to do limited twisting, turning or sliding.

Structure of a movable joint

How are bones that move protected from wear and tear? In movable joints, the surfaces of the bones are coated by smooth and slippery cartilage (a fibrous connective tissue). This serves as the cushion between the two bones. If they happen to bump one another during movement, the cartilage would act as the shock absorber. In this way, the bones will not get hurt. A sticky oil-like substance, the synovial fluid, lubricates the bone. The fluid enables the bones to move smoothly. The movable joint is surrounded by ligaments. Ligaments are tough bands of elastic tissue that join the ends of bones and prevent too much movement of the joint. A contortionist can bend and twist his/her body easily and gracefully because he/she has very loose ligaments.


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Tags

Bone, Bone Density, Bone Fracture, Bone Health, Bone Injuries, Bone Marrow, Bone Structure, Calcium, Cartillage, Collagen, Ligament, Periosteum, Red Blood Cells, Spongy Bone, Synovial Fluid, Tissues

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Comments

author avatar Denise O
24th Nov 2010 (#)

Very informative article.
I love learning new things.
Thank you for sharing.:)

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author avatar jojomen
5th Dec 2010 (#)

i can now teach a little about bones to my kids. thanks

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