2 lipid metabolism CARBOHYDRATE METABOLISM n n n
-2 -lipid metabolism CARBOHYDRATE METABOLISM
n n n *liver &muscle responsible for fat production& fat breakdown. *lipo-protein comes from absorption of protein &fat from intestine. *GH, ACTH, TSH increase release of fatty acid /
** n n *cortisone & hydro-cortisone increase fatty acid production. *Epinephrine , non epinephrine , thyroxin , insulin * decrease cholesterol secretion
n n n n 3 -protein metabolism : -responsible about tissue building , &tissue break down. -GH, gonadotrophine hormone , thyroxin participate in tissue anabolism tissue catabolism. -break down of protein give amino acid. -amino acid divided to : *1 nitrogen , end product is ammonia passed in urine & stool. *2 non nitrogen residue (ketoacid). *3 control agent (co-enzymes), enter in metabolic process.
CARBOHYDRATE METABOLISM
n n n *CHO is called quick energy. *CHO major source of energy. @Importance of CHO diet : 1 -easily grown in plants ( grains , vegetables , fruits ). 2 -low coast. 3 -stored easily.
• monosacharrides • Disacharrides • Poly sacharrides
** classification of CHO : n n n n CARBON , HYDREGEN , OXYGEN @ monosaccharide: simple ( single sugar ) glucose , fructose , galactose. glucose : -sweet sugar -found in corn syrup - comes from starch digestion. - old name dextrose. - running in the blood stream. - normal glucose level 70 -110 mg %. b-fructose : -the sweetest of simple sugar. - founds in honey , fruits. - during metabolism , fructose converted to glucose , to form energy.
n n n n n c-galactose : - produced by human digestion. -lactose change to glucose to form energy. @ Disaccharides: -two sugar molecules linked together. - sucrose , lactose , maltose. * sucrose ( glucose + fructose ). * lactose (glucose + galactose ). * maltose (glucose+ glucose ).
n n n n n a-sucrose : - table sugar. -made from sugar cane , & sugar beets. -30 -40 % contribute in the total Kcal. -found in pineapple & carrots. b-lactose : -sugar in milk is called lactose. -the least sweet disaccharides. c-maltose: -malt product of starch breakdown , & germinating cereal grains
n n @ polysaccharides: made-up of many sugar unit. - most important one is starch. Other type glycogen & dextrin & non digest able form of dietary fiber ( cellulose & noncellulose ), that provide important bulk in the diet.
n n n n *starch: - most significant poly-saccharides. -made up of many chains of simple glucose. - starch mixture is thickened by cooling , because the starch granules has gel like quality that thick the mixture. - important source of dietary CHO. - significant factor in human nutrition. -major food that contain starch include ( cereal grains , legumes , potatoes , & other vegetables ).
n n n * glycogen: - it forms during cell metabolism. - stored in small amount in the liver & muscle tissue , help to sustain normal blood glucose level during fasting period such as sleeping hours. -dietary CHO is essential to maintain these needed. - glycogen storage prevent the symptoms of low CHO intake ( fatigue , dehydration , & energy loss ).
n n n -* dextrin: -formed from break down of starch. - starch+ water = soluble starch + maltose. - soluble starch + maltose =dextrin + maltose. -dextrin + water =maltose. -maltose + water = glucose + glucose.
n n *oligosaccharides : - small portion of partially digested starch. - it is irregular form. - used in special formula for infant , or person with gastrointestinal problem , because it is easier to digest.
-* dietary fiber : - cellulose found in the framework of plants , the human cant digest it , because lack of digestive enzyme , so it form bulk of diet thus stimulate peristalsis.
n n n n ** Function of CHO: 1 -energy production. 2 -glycogen storage in the liver & muscle. 3 -regulation protein metabolism. 4 -anti-ketogenic effect { prevent formation of keton bodies from fat. keton bodies accumulated in case of {starvation , un controlled DM, very low CHO diet }. -5 - heat action [ contractile process of the heart ]. -6 -CNS stimulation { hypoglycemic shock lead to irreversible brain damage }.
n n n * Digestion of CHO: @ mechanical or muscular function that break the food into small particles. @ chemical process in which specific enzyme break down food in to smaller usable metabolic product.
n n n mouth : mastication breaks food into fine particles & mix it with salivary secretion. -salivary amylase is secreted by parotid gland act on starch to break it in to starch & maltose. Stomach , mix food with gastric secretion, no specific enzyme break down of CHO. - more food by peristalsis go to the 1 st portion of the small intestine through pyloric sphincter. Small intestine : Mechanical & chemical digestion of CHO is completed in small intestine by intestinal & pancreatic enzyme
Pancreatic enzyme: Secretion of pancreas enter the duodenum. Pancreatic amylase break down of starch & maltose. Intestinal secretion : Sucrase , lactase , maltase act on disaccharides to change it in to glucose , galactose , & fructose to be ready for absorption
** absorption of CHO: -glucose carried in to the cell to produce energy or storage. -the major glucose absorption mechanism is an active transport [ pumping system ] requiring Na as carrier substance. - villi & micro-villi absorb about 90% of digested food. -simple sugar enter portal circulation to liver
n n n n ** metabolism of CHO : - chemical process in living Organics by which energy is made available for function of entire organism - cells are the functional unit of life in human body. - the most important end product of CHO digestion is glucose. - the liver is the major site of handling glucose. -in the cell glucose is burned to produce energy through chemical reaction. -extra glucose not immediately needed for energy may changed to fat & stored
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