ADIPOSE TISSUE 



37 



Adipose Tissue. In almost all regions of the human body a larger 

 or smaller quantity of adipose or fatty tissue is present. Adipose tissue is 

 almost always found seated in areolar tissue, and forms in its meshes little 

 masses of unequal size and irregular shape, to which the term lobules is com- 

 monly applied. 



Structure. Adipose tissue consists essentially of cells which present 

 dark, sharply denned edges when viewed with transmitted light; each 

 consisting of a structureless and colorless membrane or bag formed of the 

 remains of the original protoplasm of the cell, filled with fat. A nucleus 



FIG. 45. A Lobule of Developing 

 Adipose Tissue from an Eight- Months' 

 Fetus, a, Spherical or, from pressure, 

 polyhedral cells with large central 

 nucleus, surrounded by a finely retic- 

 ulated substance staining uniformly 

 with hematoxylin. b, Similar cells 

 with spaces from which the fat has 

 been removed by oil of cloves, c. Sim- 

 ilar cells showing how the nucleus 

 with enclosing protoplasm is being 

 pressed toward periphery, d. Nucleus 

 of endothelium of investing capilla- 

 ries. (McCarthy.) Drawn by Treves. 



FIG. 46. Branched Connective- 

 Tissue Corpuscles, Developing into 

 Fat-Cells. (Klein.) 



is always present in some part or other of the cell protoplasm, but in the 

 ordinary condition of the loaded cell it is not easily or always visible. This 

 membrane and the nucleus can generally be brought into view by extracting 

 the fat with ether and by staining the tissue. 



The ultimate cells are held together by capillary blood-vessels, figure 44; 

 while the little clusters thus formed are grouped into small masses, and 

 held so, in most cases, by areolar tissue. The oily matter contained in the 

 cells is composed chiefly of the compounds of fatty acids with glycerin, olein, 

 stearin, and palmitin. 



Development of Adipose Tissue. Fat c'ells are developed from connective- 

 tissue corpuscles. In the infra-orbital connective tissue there are cells ex- 

 hibiting every intermediate gradation between an ordinary branched connec- 

 tive-tissue corpuscle and mature fat cells. Their developmental appearance 



