Stage 1 Digestion

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Stage 1 Digestion

• Molecular breakdown/absorption of
• Polysaccharides
• Lipids
• Proteins

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Starches

• MOUTH salivary amylase hydrolyzes some
  glycosidic bonds of amylose
• Formation of dextrins 3-8 glucose units
• STOMACH (pH 2)
• denatures salivary amylase stops further carb
  digestion
• DUODENUM/PANCREAS
• Secretion of pancreatic amylase completes
  digestion to maltose

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STARCHES

• SMALL INTESTINE
• Mucosa cells lining SI secrete
• lactase
• Lactose ? galactose glucose
• sucrase
• Sucrose ? fructose glucose
• maltase
• Maltose ? glucose glucose
• Absorption of monosaccharides into blood stream

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Lipids

• Mouth- Stomach no effect on lipids
• DUODENUM
• bile salts
• from the gall bladder
• emulsify fat into tiny
• droplets called micelles

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Lipids

• DUODENUM
• Pancreatic lipase hydrolyzes lipids
• lipase
• triglycerides ? monoglycerides 2 FA
• SMALL INESTINE
• Absorption into blood stream
• Transport in the blood via lipoprotein vesicles

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Proteins

• MOUTH no effect on proteins
• STOMACH contains HCl, pH 2
• a. General acid denaturing of proteins
• b. Secretion of enzyme pepsin hydrolyzes peptide
  bonds, formation of small peptides
• pepsin
• Proteins ? peptides

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Proteins

• DUODENUM/PANCREAS
• Pancreatic enzymes Trypsin/ Chymotrypsin
  hydrolyze peptides into AA
• SMALL INTESTINE
• AA are absorbed into blood stream