CONNECTIVE TISSUE 



59 



closely applied to, or even wrapped around the bundles of white fibers. 

 Fat cells occur in considerable numbers in all areolar tissue and in some 

 places are aggregated into large groups which form lobules of fatty 

 tissue. 



Dense Fibrous Tissue. In dense fibrous tissue the ground substance 

 is comparatively deficient. Large bundles of collagenous fibers are~~ar= 

 ranged in approximately parallel rows, and are so closely packed as to 



Tendon fibre 



Nucleus of a 



tendon cell, 

 surface view 



Ridges on cell 

 due to pressure' 



Tendon cells seen 

 from edge 



FIG. 68. PIECE OF TENDON FROM 



TAIL OF WHITE MOUSE. 

 Between the bundles of connec- 

 tive-tissue fibrils are cells arranged 

 in rows. Some are seen in surface 

 view, and others im optical section. 

 X 400. (From Szymonowicz-Mac- 

 Callum, "Histology and Microscopic 

 Anatomy.") 



FIG. 67. TRANSVERSE SECTION OF PORTION 



OF TENDON OF HUMAN FINGER. 

 a, three-winged cell; 6, four- winged cell; 

 c, primary bundle, completely ensheathed by 

 the wings of tendon cells, and divisible into 

 still smaller bundles of collagenous fibers 

 outlined by finer processes of the wings. 

 The individual fibers are not shown. Gold 

 chlorid. X 1000. 



form a dense, firm, highly resistant tissue. Its scanty connective tissue 

 cells are of the lamellar variety and are usually arranged in rows which 

 occupy the interstices between the parallel fiber bundles. 



Dense fibrous tissue occurs typically in tendons; in these the connec- 

 tive tissue cells often have a peculiar quadrate shape and are arranged 

 in rows of exceptional regularity (Figs. 64-67). These should be studied 

 in dissociated tendinous tissue. It also forms the ligaments, the fasciae, 

 the muscular sheaths (aponeuroses), and the enveloping capsules of many 

 of the viscera. Thus it surrounds the liver, kidney, lymphatic nodes, and 

 other organs; it also forms the valves of the heart, the tendinous rings 



