CHAPTER XIX 

 RETROGRADE PROCESSES 



Atrophy. This is a condition in which a fully devel- 

 oped organ or part undergoes a uniform diminution in 

 size, due to a disappearance of the elemental cells of the 

 organ or part. 



Hypoplasia is a condition in which from lack of devel- 

 opment an organ remains undersized or rudimentary. 



The causes of atrophy may be pathologic, from disease 

 or other injurious agency, as in atrophy of the testicle 

 after orchitis; or it may be physiologic, as the atrophy 

 of organs after their period of functional activity is 

 passed, as the atrophy of the thymus at puberty, the 

 ovaries and mammae at the menopause. 



Degeneration. The term "degeneration" is applied 

 to a condition in which a tissue is converted into 

 tissue of a different character and lower vitality. 



Cloudy Swelling. This form of degeneration occurs 

 most frequently in the kidney and liver. The normal 

 cells become swollen, cloudy, and vacuolated. It is 

 caused by fever, poisons, bacterial toxins, etc. 



Fatty Degeneration. Under the influence of various 

 toxic substances, as lead, mercury, arsenic, bacterial poi- 



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