framework in action

Your skeleton must be able to support you as you move urself and various parts of your body.That's a lot harder to do than supporting something that doesn't move.The problem is solved by the joints that are located where bones come together.Different kinds of joins determine the kind of movement you can make.The ball-and-socket is one kind of joint.Your arm and shoulder are joined in this way.The top of the arm bone is shaped like a ball.The ball fits into a shallow cuplike socket in the shoulder blade.,much the way the ball in a ballpoint pen is held in place.This arrangement,which is also found in the hip joint,let's you swing your arms and legs freely in a full circle.Another kind of joints is the hinge joints,which is like the hinges on a room door.These joints,such as the ones in your knee or elbow,allow motion mainly in one direction.The joints btw the bones of your spine allow the bones to move over one another with a gliding motion.There are even joints that prevent motion,as in the joints bt the flat bones that from your skull.Joints are surrounded by a case called a capsule.A special fluid in the capsule lets the bones move smoothly over one another,like oil on the moving parts of machine

Fascinating story

hye,i'm back..today i'll continue about the fascinating story about us that i told u yesterday,the story begin..when we were very,very young,in fact before you were born,you already has a good part of your skeleton.It was not made of bone,but of a softer material called cartilage.You still have cartilage giving shape to parts of you,such as the outer ear and the lower part of your nose.Bit by bit the cells of cartilage were replaced by bone cells.Bone cells are just as soft as any other cells,but they can do a remarkable thing.These cells take dissolved minerals,mainly calcium and phosporus,from the blood.They turn the minerals into the hard materials we hard think of as bone.The cells surround themselves with bone,and continue to live inside their self-made bony prison.This process goes on now,too,as you go on growing.The calcium and other minerals needed to form strong bone come from the foods you eat such as milk.To be continued...wait..

The living framework

Most of your body is soft material,such as muscle,and soft organs,such as the brain or stomach.Without stomach from your 206 skeletal bones,you would be shapeless mass,like a jellyfish.Some of the skeletal bones also have a 2nd important job-they protect other organs of the body. The hard skull bones,for example,protect your all-important brain.Your heart and lungs,which are also vital organs,are protected by the breastboned and by the cage formed by the ribs.The skeleton is a framework,but it's really very different from the framework of a building.Think of how much u've grown since u were born.And you aren't through growing yet!can this rigid skeleton grow with you?indeed it can!Bone is very much alive.Like the other parts of your body,bone has blood vessels and nerves,but it doesn't out as bone.Did somebody ask how it does start out?Well,stay here,i will tell this fascinating history in the next post..thanks!!

The skin

Hye,2nd posting,let's begin our look at the part of the body by looking first at the skin.We all know what hands and eyes are for,but what does the skin do? It is easy to see that the skin is a cover for the inner parts of the body.But like many other organs of the body,it has several jobs or functions.The skin is an organ that senses changes around you,and helps to keep the body temperature steady.The skin is a barrier against germs.It also removes some substances from the body and stores others temporarily.
We really should talk about ur skins,for you have two of them.The outer skin that u can see and touch is the epidermis.it is skin in which the living material has been replaced by a hard substance called keratin.as u grasp,touch,rub and wash,the cells of the epidermis are worn away,however,for the lower skin or dermis constantly produces new cell. These called fresh epidermis.