46 



THE ESSENTIALS OF HISTOLOGY. 



Elastic tissue is a variety of connective tissue in which the elastic 

 fibres preponderate. It is found most characteristically in the liga- 

 mentum nuchae of quadrupeds and the ligamenta subflava of the 

 vertebrae, but the connective tissue of other parts may also have a 

 considerable development of elastic fibres. It occurs also in an almost 

 pure form in the walls of the air-tubes, and uniting the cartilages of 

 the larynx. It also enters largely into the formation of the walls of 

 the blood-vessels, especially the arteries. 



In the ligamentum nuchae the fibres are very large and angular 

 (fig. 48) ; they often exhibit cross-markings or even transverse clefts. 

 When dragged asunder, they break sharply across ; they constantly 

 branch and unite, so as to form a close network. In transverse 

 section they are seen to be separated into small groups (fig. 49) by 

 intervening white bundles of connective tissue. 



FIG. 49. CROSS-SECTION OP ELASTIC 

 FIBRES FROM THE LIGAMENTUM 



NUCH^E OF THE OX. 



FIG. 48. ELASTIC FIBRES FROM THE LIGA- 

 MENTUM NUCH^E OF THE OX, SHOWING 

 TRANSVERSE MARKINGS ON THE FIBRES. 



Elastic tissue does not always take the form of fibres, but may occur 

 as membranes (as in the blood-vessels). Sometimes the fibres are very 

 small, but their microscopical and chemical characters are always very 

 well marked (see p. 40). 



Fibrous tissue is almost wholly made up of bundles of white fibres 

 running in a determinate direction. These again are collected into 



