BIOCHEM

• Lipids - Heterogenous group of water insoluble organic molecules that can be extracted from the tissues by non polar solvents
• Fat Soluble Vitamins have regulatory or coenzyme role in the body.
• Prostaglandins and Steroid Hormones play major roles in the control of Body's Homeostasis
• More than 95% are triglycerides and other are cholesterol, cholesteryl ester, phospholipids, and Unesterified fatty acids.
• the dietary sources of lipids are animal sources and Vegetable sources
• Animal sources have dairy product like meat, butter, ghee, meat, and fish, pork, eggs that can be sources of lipids.
• Vegetable sources have a cooking oils like sun flower oil, mustard oil, ground nut oil and fats from other vegetable sources that can be source of lipids
• Lipids is a major source of energy for the body
• Digestion in Mouth

  Hydrolysis of triacylglycerols is initiated by lingual and gastric lipases, which attack the sn-3 ester bond forming 1,2-diacyglycerols and free fatty acids, aiding emulsification
• Lingual Lipase is Secreted by dorsal surface of tongue
• Lingual Lipase iss active at pH (pH 2.0 - 7.5)
• Lingual lipase has optimum pH 4.0 - 4.5
• Enzymatic action continues in stomach
• Short chain fatty acids, released are absorbed directly from the stomach wall and enter the portal vein
• Triglycerides are degraded by lipases to form free fatty acids and glycerol
• Gastric Lipase- secreted in small quantit
• Digestion in Stomach requires the presence of Ca++
• Digestion in Stomach is not effective for long chain fatty acids, most effective for short and medium chain fatty acids
• Milk, egg yolk and fats containing short chain fatty acids are suitable substrates for its action
• fats delay the rate of emptying of stomach
• Enterogastrone inhibits gastric motibility and retards the discharge of bolus of food from the stomach
• Fats have a high satiety value
• Play important role in lipid digestion in neonates since milk is the main source of energy
• Important digestive enzymes in pancreatic insufficiency such as Cystic fibrosis or other pancreatic disorders
• Lipids are hydrophobic , and thus are poorly soluble in the aqueous environment of the digestive tract
• The digestive enzyme, Lipase, is water soluble and can only work at the surface of fat globules
• Digestion is greatly aided by emulsification, the breaking up fat globules into much smaller emulsion droplets
• Triacylglycerol digestion occurs at lipid-water interfaces
• Rate of TAG digestion depends on surface area of the interface which is increased by churning peristaltic movements of the intestine
• The critical process of the emulsification takes place in the duodenum
• Small intestine is the major site of fat digestion
• The digestion is effective because of the presence of pancreatic lipase and bile salts
• Bile salts act as effective emulsifying agents for fats
• Secretin - Increases the secretion of electrolytes and fluid components of pancreatic juice
• Pancreozymin of CKK - PZ stimulates the secretion of the pancreatic enzymes
• Cholecystokinin of CKK - PZ causes the contraction of the gall bladder and discharges the bile in to the duodenum
• Hepatocrinin - Released by the intestinal mucosa, stimulates more bile formation which is relatively poor in bile acid content
• Pancreatic Lipase is for the digestion of triglycerides
• Phospholipase A2 - for the digestion of phospholipids
• Cholesterol esterase - for the digestion of cholesteryl esters