CHAPTEE V 



INTERNAL RESTITUTIVE SECEETIONS 



CONTENTS. 1. Gastric absorption. 2. Intestinal absorption. 3. Fate of the 

 different groups of food-stuffs after absorption. 4. Importance of living epithelium 

 to absorption of crystalloid substances (salts and sugars). 5. Absorption of 

 neutral fats in form of soaps ; synthetic regeneration by epithelium of intestine. 



6. Absorption of proteins, proteoses, and peptone ; synthetic regeneration. 



7. Mechanism of internal secretion of absorbed and regenerated compensation- 

 products. 8. Formation of glycogen (amylogenesis) and glucose (glycogenesis) by 

 hepatic cells. 9. Hepatic glycogenesis an 'internal secretion ; regulation by 

 nervous system. 10. Derivation of hepatic and muscular glycogen from carbo- 

 hydrates of food. 11. Derivation of glycogen from decomposition of proteins and 

 fats (diabetes mellitus from pathological causes, experimental diabetes from phloridzin 

 and removal of pancreas). 12. Accumulation of alimentary fat ; adipogenesis. 

 13. Accumulation and consumption of alimentary protein. 14. Protective function 

 of intestinal epithelium and liver. Bibliography. 



IN proportion as the food-stuffs are altered by digestion in 

 their passage through the alimentary canal, and are transformed 

 from insoluble into soluble substances, from such as are not 

 diffusible into such as are readily diffused, they are absorbed by 

 the epithelium of the gastro-intestinal mucous membrane, and 

 are converted into Chyle, which is then poured out by internal 

 secretion into the lymph sinuses of the mucosa. Chyle there- 

 fore denotes, not the total product of digestion, but rather the 

 sum of such natural or digested food-stuffs as are discharged 

 into the lymph torrent by internal secretion, after their partial 

 regeneration into the constituents of lymph and blood which is 

 the synthetic or anabolic function of the living cells of the 

 absorbing mucous surface. Hence the concept of " chyle " is 

 purely theoretical. The milky fluid which can be collected 

 during digestion from a fistula of the thoracic duct and from the 

 larger cliyliferae or lacteal vessels is not really the whole of the 

 chyle. It does not contain all the substances absorbed and 

 transformed by the gastro-intestinal mucous membrane, in their 

 relative proportions, since a large part of these substances are taken 

 up by the blood capillaries of the mucous coat (particularly in the 

 villi of the small intestine) and carried to the liver by the portal 

 system, while another considerable part are absorbed by the solitary 



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