Org med labs

• Enzyme


  Catalysts produced as a result of cellular activity that occur in abundance in plant and animal tissue. Most enzymes end in "ase"
• Six major categories of enzymes

  • Oxidoreductases
  • Transferases
  • Hydrolases
  • Lyases
  • Isomerases
  • Ligases
• Saliva


  Three pints of saliva produced daily, 99% water and 1% proteins, enzymes, and electrolytes. Contains the enzyme amylase which breaks down starches, initiates fat breakdown, and starts digestion
• Drugs and dry mouth


  Several hundred medications can cause or exacerbate xerostomia (dry mouth), including antihypertensives, antidepressants, analgesics, tranquilizers, diuretics, and antihistamines. Dry mouth drastically alters patients' lives
• Digestive enzymes


  • Lipases
  • Proteases and peptidases
  • Amylases
  • Nucleases
• Pepsin


  One of the major enzymes involved in gastric digestion, has a precursor called pepsinogen
• Physiologic functions of gastric exocrine secretions


  • Killing or suppression of growth of ingested microorganisms
  • Facilitation of duodenal inorganic iron absorption
  • Stimulation of secretin release
  • Suppression of antral gastric release
  • Initiation of peptic hydrolysis of dietary proteins
  • Liberation of vitamin B12 from dietary protein
  • Binding of Vitamin B12 for subsequent ileal uptake
  • Initiation of hydrolysis of dietary triglycerides
  • Protection against noxious agents
• Function of stomach


  Initiates digestion by exocrine secretions such as acid and pepsin, under control of endocrine secretion of hormones that also coordinate intestinal motility. Also stores and mechanically disrupts ingested food
• Three pancreatic enzymes


  • Pancreatic proteases (such as trypsin and chymotrypsin)
  • Pancreatic amylase
  • Pancreatic lipase
• Chemical digestion in the small intestine

  Enzymes enter the small intestine in response to the hormone cholecystokinin, which is produced in response to the presence of nutrients. The hormone secretin also causes bicarbonate to be released into the small intestine from the pancreas to neutralize the acid coming from the stomach
• Three major classes of nutrients that undergo digestion

  • Proteins
  • Lipids
  • Carbohydrates
• Protein digestion


  Proteins are degraded into small peptides and amino acids before absorption. Their chemical breakdown begins in the stomach and continues through the large intestine. Proteolytic enzymes, including trypsin and chymotrypsin, are secreted by the pancreas and cleave proteins into smaller peptides
• Lipid digestion


  Lipids (fats) are degraded into fatty acids and glycerol. Pancreatic lipase breaks down triglycerides into free fatty acids and monoglycerides. Bile salts emulsify the triglycerides to aid access by the water-soluble pancreatic lipase
• Carbohydrate digestion


  Some carbohydrates are degraded into simple sugars, or monosaccharides (e.g., glucose, galactose) and are absorbed by the small intestine. Pancreatic amylase breaks down some carbohydrates (notably starch) into oligosaccharides. Brush border enzymes then further break down oligosaccharides. Cellulose is not digested as humans lack the enzyme to split the beta-glucose bonds
• Enzymes end in "ase"
• Pepsinogen


  Precursor of pepsin
• Alkali


  Protects pepsinogen
• Enzyme


  Catalysts produced as a result of cellular activity that occur in abundance in plant and animal tissue. Most enzymes end in "ase"
• Six major categories of enzymes

  • Oxidoreductases
  • Transferases
  • Hydrolases
  • Lyases
  • Isomerases
  • Ligases
• Saliva


  Three pints of saliva produced daily, 99% water and 1% proteins, enzymes, and electrolytes. Contains the enzyme amylase which breaks down starches, initiates fat breakdown, and starts digestion
• Drugs and dry mouth


  Several hundred medications can cause or exacerbate xerostomia (dry mouth), including antihypertensives, antidepressants, analgesics, tranquilizers, diuretics, and antihistamines. Dry mouth drastically alters patients' lives
• Digestive enzymes


  • Lipases
  • Proteases and peptidases
  • Amylases
  • Nucleases
• Pepsin

  One of the major enzymes involved in gastric digestion, has a precursor called pepsinogen
• Physiologic functions of gastric exocrine secretions


  • Killing or suppression of growth of ingested microorganisms
  • Facilitation of duodenal inorganic iron absorption
  • Stimulation of secretin release
  • Suppression of antral gastric release
  • Initiation of peptic hydrolysis of dietary proteins
  • Liberation of vitamin B12 from dietary protein
  • Binding of Vitamin B12 for subsequent ileal uptake
  • Initiation of hydrolysis of dietary triglycerides
  • Protection against noxious agents
• Function of stomach


  Initiates digestion by exocrine secretions such as acid and pepsin, under control of endocrine secretion of hormones that also coordinate intestinal motility. Also stores and mechanically disrupts ingested food
• Three pancreatic enzymes

  • Pancreatic proteases (such as trypsin and chymotrypsin)
  • Pancreatic amylase
  • Pancreatic lipase
• Chemical digestion in the small intestine

  Enzymes enter the small intestine in response to the hormone cholecystokinin, which is produced in response to the presence of nutrients. The hormone secretin also causes bicarbonate to be released into the small intestine from the pancreas to neutralize the acid coming from the stomach
• Three major classes of nutrients that undergo digestion

  • Proteins
  • Lipids
  • Carbohydrates
• Protein digestion


  Proteins are degraded into small peptides and amino acids before absorption. Their chemical breakdown begins in the stomach and continues through the large intestine. Proteolytic enzymes, including trypsin and chymotrypsin, are secreted by the pancreas and cleave proteins into smaller peptides
• Lipid digestion


  Lipids (fats) are degraded into fatty acids and glycerol. Pancreatic lipase breaks down triglycerides into free fatty acids and monoglycerides. Bile salts emulsify the triglycerides to aid access by the water-soluble pancreatic lipase
• Carbohydrate digestion

  Some carbohydrates are degraded into simple sugars, or monosaccharides (e.g., glucose, galactose) and are absorbed by the small intestine. Pancreatic amylase breaks down some carbohydrates (notably starch) into oligosaccharides. Brush border enzymes further break down oligosaccharides. Cellulose is not digested as humans lack the enzyme to split the beta-glucose bonds
• OXIDOREDUCTASES


  Also known as dehydrogenase and oxidase

  • Alcohol dehydrogenase
  • Glutamic dehydrogenase
• Transferases


  Catalyze the transfer of one-carbon groups

  • Aldehyde
  • Ketone
  • Phosphorus
  • Sulfur groups
• Lyases


  Removal of groups from substrates by mean of other than hydrolysis, leaving double bonds

  • Ketone
  • Aldehyde
  • Carbon-oxygen lyases
• Hydrolases


  Catalyze hydrolysis of ester, ether, peptide and other bonds

  • Pensin
  • Rennin
• Isomerases


  Catalyze interconversion of optical and geometric isomers

  • Enzymes
• Ligases


  Catalyze the linking together of two compounds coupled to the breaking if a pyrophosphate bond

  • Succinate co-a
  • Acetyl co-a
• 3 role specific proteins in saliva

  • Antibacterial histatins
  • Protective statherins
  • Lubricating mucins
• Drugs that affects the salivas role in digestion

  • Antihypertensives
  • Antidepressants
  • Antihistamines
  • Tranquilizer
  • Diuretics
• Main site of digestion


  Oral cavity

  Small intestine

  Stomach