CARBOHYDRATE METABOLISM -2-lipid metabolism CARBOHYDRATE METABOLISM

*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 /

** *cortisone & hydro-cortisone increase fatty acid production . *Epinephrine ,non epinephrine ,thyroxin ,insulin * decrease cholesterol secretion

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 . *2non nitrogen residue (ketoacid). *3control agent (co-enzymes),enter in metabolic process .

CARBOHYDRATE METABOLISM

*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 : 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 .

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 ).

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

@ 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 .

*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 ).

* 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 ).

-* dextrin: -formed from break down of starch . - starch+ water = soluble starch + maltose . - soluble starch + maltose =dextrin + maltose . -dextrin + water =maltose . -maltose + water = glucose + glucose .

*oligosaccharides :- - small portion of partially digested starch . - it is irregular form . - used in special formula for infant , or person with gastro-intestinal 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 .

** 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 }.

* 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 .

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 1st 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

** 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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