56 



GENERAL CONCEPTS 





Adipose, tissue 



Figure 3.12. 



Fibrous cartila.^<z. 

 (ajrticular) 

 Diagram of the types of connective tissue anci their location in the knee 



joint. 



tough, vinbranched, flexible, but relatively inelastic collagen fibers, and 

 long, branched, elastic fibers. Adipose tissue is rich in tat cells, spe- 

 cialized connective tissue cells which store large quantities of fat in a 

 single drop in the cytoplasm. Ligaments and tendons are specialized 

 kinds of fibrous connective tissue. Tendons are composed of thick, closely 

 packed bundles of collagen fibers, which form flexible cables that con- 

 nect a muscle to a bone or to another muscle. A ligament is funda- 

 mentally similar in constitution to a tendon and connects one bone to 

 another. An especially thick mat of fibrous connective tissue is located 

 in the lower layer of the skin of most vertebrates; when this is chemically 

 treated— "tanned"— it becomes leather. 



The supporting skeleton of vertebrates is composed of cartilage or 

 bone. In some, for example the sharks, the skeleton is made entirely of 

 cartilage. Cartilage appears as the supporting skeleton in the embryonic 

 stages of all vertebrates, but is largely replaced in the adult by bone. 

 Cartilage can be felt in man as the supporting framework of the pinna 

 of the ear (the external ear flap) or the tip of the nose. It is made of a 



