Human Bile.

Human Bile

Bile is  a viscous,  greenish  yellow fluid,  sour in  taste.  It is  secreted  by hepatocytes  (liver cells)  of the liver.  Around  0.8  to  1.0 litre  of bile are produced each day  and stored  and concentrated  in  the  gall bladder. Bile  is secreted  into  the  duodenum  through  the common  bile  duct.  The hormone cholecystokinin  controlls  the  flow  of bile. Composition  of bile:  Bile is  composed  of  about  98%  water, 0.8%  bile  salts,  A.2%o bile pigments,  0.7% inorganic  salts  and 0.6% cholesterol.  Sodium  taurocholate and sodium glycocholate  are the bile  salts.  Among the inorganic  salts,  sodium  bicarbonate  is important. No  enzymes are  present in  the  bile.  Biliverdin  and  bilirubin are  main  bile pigments. The bile  pigments are  produced  in  the  liver  from  the haem  of haemoglobin  in the  process  of  the  destruction of  red blood  cells. Bile pigments have  no function and  are excretory  products. Functions of bile:  The functions of the bile  are:

i.  Emulsifies  fats  (breaks  large  fat  or  oil droplets into  an emulsion  of microscopic

droplets),  a process  that  massively  increases  the  surface  area available for fatdigesting  enzymes  to attack.

ii.  Neutralises  the  acidic  chyme from  the  stomach  and  create the  ideal  pH for  intestinal

enzymes.

iii.  Stimulates  peristalsis  (rhythmic  involuntary  muscular contractions)  in  the duodenum

and  ileum.

iv.  Allows  the  excretion  of cholesterol,  fats  and bile  pigment.