CONNECTIVE TISSUES 



around the kidneys, between the furrows on the surface of the 

 heart and in bone marrow. It has a rich blood supply. 



(5) Cartilage. Those tissues in which the intercellular 

 substance has undergone condensation until it appears homo- 

 geneous are classified as cartilage. Consequent upon the 

 differences exhibited by the intercellular matrix it is divided 

 into the following varieties: (a) 

 Hyaline, (b) elastic and (c) fibrous. 



(a) Hyaline cartilage is of firm 

 consistence, considerable elasticity 

 and is pearly blue in color. It is 

 enveloped in a fibrous membrane, 

 the perichondrium, from the vessels 

 of which it derives its nutrition. It 

 is composed of cells, irregular in 

 outline and arranged in patches of 

 various shapes, which are embedded 

 in a homogeneous matrix. The 

 articular surfaces of bones, the 

 costal cartilages, and the larger 

 cartilages of the larynx, trachea and 

 bronchi, and, also, those of the nose 



and Eustachian tube are formed of this variety. In the em- 

 bryo this cartilage forms nearly the whole of the future bony 

 skeleton. 



(b) Elastic cartilage is characterized by the presence of an 

 abundance of elastic fibers in the matrix. These resemble 

 those found in the yellow variety of elastic tissue. This variety 

 of cartilage is found in the external ear, epiglottis, cornicula 

 laryngis and Eustachian tube. 



(c) Fibrous cartilage is characterized by the presence of a 

 large amount of white fibrous tissue in the matrix. It combines 

 the toughness and flexibility of fibrous tissue with the firmness 

 and elasticity of cartilage. It is found chiefly in the interver- 



FIG. 12. Section of hyaline 

 cartilage. 



From the end of a growing bone, 

 showing a decrease in the intercel- 

 lular substance compared with the 

 number of cell-elements, which are 

 arranged in rows. (Yeo.) 



