HYPERTROPHY AND HYPERPLASIA. 289 



hyperplasia is more common in those of lower function, where the 

 formative powers of the cells are less in abeyance. 



COMPENSATORY HYPERTROPHY is a term applied to functional 

 hypertrophy or hyperplasia following the destruction of an organ or 

 part of an organ. This leads to an increase of the work demanded of 

 other parts capable of performing the function normally carried on 

 by the part destroyed, or capable of assisting the function that has 



FIG. 259. 



$3 



Necrosis of part of an hepatic lobule, (v. Meister.) a, necrosed cells, the nuclei of which 

 have lost their affinity for dyes ; b, hypertrophic cells with large nuclei ; c, detritus of 

 blood-corpuscles in the capillaries. Section taken eighteen hours after removal of a por- 

 tion of the liver in a rabbit. The section is taken at the margin between that tissue 

 which is affected with necrosis and that which retains life, but is stimulated to prolifera- 

 tion by the irritative effects of the amputation. After a while the hypertrophied epithe- 

 lial cells will divide by karyokinesis and attempt a restitution of the lost tissue a species 

 of compensatory hyperplasia. 



suffered diminution. Thus, disease of one kidney may indirectly 

 occasion hypertrophy of the other kidney, or, more properly, hyper- 

 plasia of its functional epithelium, or chronic interstitial nephritis 

 affecting both kidneys may lead to hypertrophy of the heart by 

 throwing more labor upon that organ in order that the remaining 

 renal parenchyma may perform the work demanded of the kidneys. 

 In like manner the auxiliary muscles of respiration may become 

 hypertrophic in cases of embarrassed respiration. 1 



Functional hypertrophy may also find expression among the con- 



1 Attention has already been called to the hypertrophies of the hypophysis and 

 parathyroids in cases of thyroidectomy or disease of the thyroid gland (see p. 191). 

 19 



