APPLIED PHYSIOLOGY 



yet it can be bent somewhat without breaking. It is 

 twice as strong as an oak stick of the same size. 



307. Structure of bone. A bone is made of living cells 

 fed by the blood. From the cells there go out fine strings 

 of connective tissue. Lime is mixed among the strings 

 like starch among the fibers of a linen collar. This makes 



a bone cells. 



Thin slice of bone ( X 200) . 



b Haversian canal, containing blood vessels and nerves. 



the bones hard. About one third of a bone is made of the 

 living cells and two thirds is lime. Under a microscope 

 we can see that the cells form circles around small blood 

 tubes. 



A bone is covered with a tough membrane called the 

 periosteum. The periosteum forms new cells and makes 

 the bone grow. If the bone is removed and its -periosteum 

 left, this will form a new bone in a few weeks. Bone 

 grows and wastes away, but it changes much slower than 

 any other part of the body. 



The place where bones join together is a joint. Some 

 joints can bend and others cannot. 



