96 



THE TISSUES 



the individual librils do not branch, groups of fibrils pass from one 

 bundle to another. There is little ground substance and cells are 

 comparatively few. The latter are, however, so characteristic as 

 to have received the name of tendon cells (Fig. 43). They are irregu- 

 larly rectangular cells, have rather more breadth than length and are 

 arranged in characteristic rows between the fibre bundles. The cell 

 margins are contiguous and the 

 usually excentric nuclei tend to lie 

 in adjacent sides of two cells, thus 

 giving the cells the appearance of 

 being arranged in pairs (Fig. 42). 

 Thin plate-like extensions of the 



— A 



— B 



Fig. 43. Fu;. 44. 



Fig. 43. — Tendon Cells from the Tail of a Rat. Stained by methylene-blue {intra 

 vitam). (Bohm-Davidoff.) 



Fig. 44. — Pavement Endothelium of Tendon of Rat. A , intercellular substance im- 

 pregnated with silver nitrate; 5, tendon fibres, Xirs- (Branca.) 



cell (Fig. 43) pass into the ground substance between the fibre 

 bundles and when the cell is seen on flat, the greater thickness of 

 the cell through the extensions gives the optical effect of dark lines 

 in the cell body. 



Aponeuroses. — In thin aponeurotic tissue the fibres are disposed 

 in two planes, the fibres of one plane running approximately at 

 right angles to those of the other plane. The cells resemble tendon 

 cells and he. upon the fibre bundles. In thicker aponeuroses the 

 fibres are arranged in planes but their disposition is more irregular. 



ELASTIC TISSUE 



Elastic fibres occurring in fibrous connective tissue have been 

 described. When the elastic fibres predominate the tissue is known 

 as elastic tissue. Almost pure elastic tissue is found in the Uga- 

 mentum nuchai of quadrupeds. In man it occurs mainly in the 

 ligamenta subflava, in some of the laryngeal ligaments, in the walls 



