How are the small intestines in mammals adapted to their functions?

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Small  intestines  consists  of  the  duodenum  and  the  ileum;  most  digestion  of  food  occurs  in  the duodenum;  bile  from  the  gall  bladder  of  the  liver  is  secreted  through  the  bile  ducts;  and  it  is  used to  emulsify  fats/break  fat  particles  into  tiny  droplets;  to  increase  the  surface  area  for  enzyme action;  the  pancreaset  secretes  pancreatic  juice  to  the  duodenum;  the  juice  contains  pancreatic amylase ;  that helps  to  breakdown  the  remaining  starch  into  maltose; trypsin; (that  is  secreted  in its  inactive  form,  trypsinogen,  and  activated  by  enterokinase  enzyme );  hydrolyses  proteins  into shorter  peptides; pancreatic  lipase ;  converts  lipids  into  fatty  acids  and  glycerol ;  sodium  hydrogen carbonate is  also  produced;  to  neutralize  the  acidic  chyme  from  the  stomach ;  and  provide  a suitable  alkaline  medium  for  pancreatic  and  other  intestinal  enzymes ;  the  ileum  is  long;  and narrow;  to  increase  the  surface  area  for  complete  digestion  of  food;  and  maximum  absorption  of digested  food;  highly-coiled;  to  reduce  speed  of  food  flow;  for  maximum  digestion;  and absorption;  presence  of  villi;  and  microvilli;  to  increase  surface  area;  for  maximum  absorption; dense  network  of  capillaries;  to  transport  blood;  for  efficient  transport  of  absorbed  food; presence  of  lacteals  in  the  villi;  for  absorption  of  fatty  acids  and  glycerol  molecules;  presence  of enzymes:  Lipase;  for  digestion  of  lipids  into  fatty  acids  and  glycerol;  maltase;  for  digestion  of maltose  to  glucose  molecules;  peptidase;  for  breakdown  of  peptides  into  amino  acids;  sucrase; for  digestion  of  sucrose  into  glucose  and  fructose;  lactase;  for  digestion  of  lactose  into  glucose and  galactose;  goblet  cells;  produce  mucus;  to  lubricate  the  walls  of  the  ileum;  for  smooth  flow of  food;  coats  the  walls  of  ileum  to  prevent  digestion  by  peptidase  enzyme;  Max.  20  mks 

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