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Metabolic effect of hormones , Tissue and organ metabolism - Heart , Liver ط Hormonal Regulation of fuel metabolism ط Metabolic effects of hormones : Epinephrine ,Glucagon ,Insulin ط Cardiac Muscle : Structure and metabolic characters
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Metabolic effect of hormones , Tissue and organ metabolism- Heart , Liver ط Hormonal Regulation of fuel metabolism ط Metabolic effects of hormones : Epinephrine ,Glucagon ,Insulin طCardiac Muscle : Structure and metabolic characters ط Fuel used , interaction of Fat and Carbohydrate metabolism ط Effect of extra work طLiver : Metabolic functions of the liver ط Fuels used by the liver, Integration of metabolism and role pf the liver L5 884-897, 902-909 ; D4 1018 -9
Heart Muscle · Like skeletal musle, does not store large amount of lipid and glycogen for ATP fig23.12 · But have small amount of phosphocreatine · Differ from skeletal muscle in that it is continuously active · Has complete aerobic metab · Abundant in mitcoh (1/2 vol of cell) · Good blood supply · The fuel is mainly free FAs but also glc and KB · Oxidation is through TCA cycle and phosphorylation to generate ATP
Liver · Process and distribute nutrients fig23.12, fig23.14, fig23.15 · Diet (lipid, carb, prt) are enz hydrolyzed, absorbed go to liver (Kupffer cells & Hepatocyte) · Bilirubin (bile), BA (chol), glycogen (glc), TG (FA), glc and FA oxid
Tissue and organ metabolism: Brain and Adipose tissues طBrain : Energy needs and metabolism of the brain ط Fuels used by the brain طAdipose tissue : Metabolic role of adipose tissue , Effect of hormones on it ط Interrelationship of carbohydrate and lipid metabolism L5 897-902 ; D4 269-70 , 920-1 , 928-9
Adipose Tissue · Consists of adiposcytes (fat cells) fig23.16 · Stores 65% of TG · Have glycolytic metab, TCA cycle, oxid phosph, converts glc to FA to be stores as TG · Lipoprotein arriving from liver are VLDL · Lipase release FAs (70% are re-esterfied to TG) · cannot used glycerol (no glycerol kinase) · Glc come from pyr by PEP CK · Brown adipose tissue (infants) generates heat (not ATP)
Brain · Uses energy for transmission of electrical impulse · Neurons use only glc as fuel fig23.20 · KB (b-HB) oxid by glycolysis and TCA cycle · Astrocytes are major cells in brain can oxid FA (as KB) uses 20% of O2 fig23.21 · Brain store little glycogen, so it is dependent on bld glc · Electron flow (resp chain) provides almost all ATP used by neurons · Memb contains Na+/K+ pump (ATPase antiport): 3 Na+ out / 2K+ in causing electrical signal (action potential)
Blood · Carries O2 metabolites and hormones · Transports nutrients from s.intest to liver and AT then to other tissues · Transports waste from tissues to kidneys for excretion · Transport hormones from one tissue to another (signal) · Adults have 5-6 litres bld: 50% are cells and 50% plasma fig23.22 · Fuels are provided by FA, Glc, KB fig23.29
Integration A. Tissues: · Glycolysis occur in all cells (no O2) fig7.2 except brain fig7.3 · RBCs lack mitoch unable to convert pyr to CO2 & H2O · Cornea, lens, retina have limited bld supply & lack mitoch · Kidneys, testis, leukocytes & w. muscle are almost dependent on glycolysis for ATP (have few mitoch) B. Others: · Stores polysach. (starch / glycogen) lead to glc source · Disach. (lactose, sucrose) lead to glc as source · Hormones (Glg/Ins) lead to glc control