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Why do I need a skeleton?

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Why do I need a skeleton? Bones provide the framework that holds the whole body together. Without a skeleton you would simply flop about, and you would not be able to move.The skeleton also gives protection to delicate organs such as the brain, heart and lungs. It acts as a support to the soft parts of the body.

The skeleton also provides a system of levers that your muscles can work on, enabling you to make all your movements.

Which is the largest bone in the body?

The thigh bone, or femur, is the largest single bone in the body. It is also the strongest bone, because it has to support all of our weight. An adult male who is 1.8 m tall has a femur 0.5 m in length.

Which is the smallest bone in the body?

The smallest bone in the body is called the stirrup. It is in the middle ear and is part of the system that carries sound signals to the brain. At only 3 mm long, the stirrup is about the size of a grain of rice. It is connected to two other very small bones called the hammer and anvil. All three of these bones are joined to the eardrum, where sound is collected before it is sent in the form of nerve signals to the brain.

What are bones made of?

Bones are made of hard minerals that are supported by tough fibres called collagen. Most of the substance of a bone is made of a stony material called calcium phosphate. It is a hard but brittle material.The collagen strands reinforce this brittle material to prevent it from breaking easily.

Are bones alive?

Bones consist of a solid stony material that is laid down in layers by living bone cells. New bone is constantly being reabsorbed and then replaced, to keep it healthy. The surface of a bone is covered by a skin that is full of nerves, so it hurts when you bruise or break a bone. Inside the bone are blood vessels and marrow, a soft material in which new blood cells are produced. When people get old, their bones may become very spongy and weak, and so they are more prone to breakage.

How do bones grow?

The bones of a baby inside its mother's womb are made up of a rubbery material called cartilage. As the body grows, this cartilage is gradually replaced by hard bone. The long bones of the body, such as the thigh bone, grow from their ends.This explains why teenagers suddenly increase in height during a growth spurt.

The skeleton provides support and protection for the body, the delicate organs in the abdomen, and the brain in the skull. It also provides a firm anchor for muscles, allowing us to move freely.

How can bones heal themselves after a break?

Bones are alive, and so the bone cells can gradually replace and repair the solid bone when it is broken. The damaged material is gradually absorbed back into the body, and the bone cells secrete more hard bone. This eventually builds up into a thickened area on the repaired bone, which is actually stronger than the original bone.

What are joints?

A joint is the point where two or more bones come together. Joints can be fixed, such as those that hold together the rounded part of the skull, or they can allow movement, such as your knees and elbows. Straps of tough flexible material called ligament hold together the bones in a joint.

Vanishing bones

Adults have about 206 bones. The number varies a little because some people have extra rib bones, or more bones in their hands or feet. A newborn baby has more than 300 bones, but some of these fuse (join) together as we grow. The skull is actually made up of 29 bones. Most of the skull bones are firmly joined together in adults, allowing only the jaw to move.

Bones in space

Constant use keeps the bones strong, so lack of exercise is one of the reasons why old people's bones can become weak. Astronauts orbiting the Earth for long periods lose a lot of their solid bone. They can lose as much as four grams of bone in a month. In order to keep their bones healthy, astronauts have to take regular exercise even though they are weightless.

How do joints work?

The ends of most bones are covered with tough rubbery cartilage, which cushions them from impact as we move.

Many joints are lubricated with an oily liquid called synovial fluid so they can bend freely. Synovial fluid is held in a bladder between the layers of cartilage on the ends of the bone.These lubricated joints can move freely and without friction.

Can joints wear out?

Joints can become diseased or wear out after a lifetime of use. When this happens, the cartilage or the fluid inside the joint gradually disappears. The joint becomes hard to move and may be very painful.

How many joints do I have?

The human body has more than 100 joints. Some joints move like a simple hinge, such as those in the elbows and knees. Other joints move in all directions, such as the shoulder joint or the base of the thumb. Joints in the spine allow only a small amount of movement between the vertebrae that protect the spinal cord. Joints such as the bones of the skull and those joining the two sides of the pelvis are locked firmly together so they do not move at all.

The knee is a typical load-bearing joint. The ends of the bone are cushioned by a pad of cartilage to cushion them from impact. Wear and tear is minimized by a lubricant called synovial fluid.


Tags: human, body, bones, skeleton



Category: Education  - ( Education Archive)

Date Added: 21 December '11


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