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Digestion & Absorption


Protein → Mouth   (mechanical digestion) 

                       ↓

                Stomach :  • HCL gets released and Unfolds the protein chain as well as activates PEPSIN                                                                                          ↓             • Pepsin breaks down proteins into Polypeptides

                  Small Intestine 

  1.            Duodenum  -  • Pancreas releases pancreatic juices into duodenum.
  2.                    ↓                •  Pancreatic juice contains Bicarbonate Buffer,
  3.                    ↓                •  Bicarbonate Buffer neutralizes HCL to protect intestinal environment                                                                                         ↓
  4. 2.  Jejunum & Ileum -  • Intestinal Cells / Enterocytes cells               
  5.                                          • Free Amino Acids, Polypeptides, Tripeptides goes into intestinal cells and everything becomes free amino                                              acids         

Free Amino Acids goes to liver via hepatic portal  vein then to general blood  circulation

Protease/ Proteolytic Enzymes - TRYPSIN, CHYMOTRYPSIN, CARBOXY PEPTIDASE,

List of major protein-digesting enzymes (proteolytic enzymes)


EnzymeLocationFunction (short)
PepsinStomachStarts protein digestion
TrypsinSmall intestine (pancreas)Breaks peptides
ChymotrypsinSmall intestine (pancreas)Digests proteins
CarboxypeptidaseSmall intestine (pancreas)Removes amino acids from end
AminopeptidaseSmall intestine (intestinal lining)Releases amino acids
DipeptidaseSmall intestine (intestinal lining)Splits dipeptides

 Simple digestion order

  1. Pepsin → stomach

  2. Trypsin + Chymotrypsin + Carboxypeptidase → pancreas → small intestine

  3. Aminopeptidase + Dipeptidase → intestinal wall → final amino acids

Final product: Amino acids absorbed into blood.