CARTILAGE 67 



has discovered robust fibers extending also from cell to cell, resembling 

 somewhat white fibers, but unrelated by transition elements to, and dif- 

 fering microchemically from, collagenous fibers. They are said to be 

 similar to the fibrils of neuroglia cells of nervous tissue and to the 

 border or myoglia fibrils of plain muscle cells. 



BLOOD AND NERVE SUPPLY OF THE CONNECTIVE TISSIKS 



The connective tissues, but especially the areolar variety, form a 

 supporting substance through which the various blood and lymphatic 

 vessels and nerve trunks are distributed to all portions of the body. 

 Within the connective tissues these vessels are everywhere present, and 

 from them the connective tissue itself receives its supply of capillary 

 vessels and terminal nerve fibrils. 



The vascular supply of the connective tissues is very abundant. 

 Small arteries, which are derived from the main trunks, form a capillary 

 plexus throughout the tissue, the capillaries finally reuniting to form the 

 venules. 



It is in this capillary plexus that the fluid portions of the blood exude 

 into the surrounding perivascular lymphatic or tissue spaces of the con- 

 nective tissue. The tissue juices which arise in this manner are most 

 active agents in the physiological processes of assimilation. From the 

 tissue juice spaces, lymph reenters the abundant capillary lymphatic 

 vessels to be finally returned to the venous blood. This transfer is 

 mediated by process of filtration and osmosis, the tissue spaces being 

 generally regarded as closed spaces making no direct connection with 

 the lymphatic terminals. Of the several varieties of connective tissue, 

 the adipose possesses the most abundant blood supply ; the lymphoid, on 

 the other hand, is most richly supplied with lymph. 



Abundant nerves are distributed to the connective tissues, some of 

 which, the sympathetic nerves, supply its blood-vessels while others, 

 medullated, terminate in special forms of sensory nerve end-organs. 



CARTILAGE 



Cartilage is a dense, firm, but elastic substance, resembling connective 

 tissue in that it is developed from similar mesodermal cells. It contains 

 a ground substance, the cartilage matrix, and at times, fibers which 

 may be either collagenous fibers or elastic. The presence, absence, or 



