Digestion and absorption of dietary carbohydrates Pathways of glucose metabolism: glycolysis

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Digestion and absorption of dietary carbohydrates Pathways of glucose metabolism: glycolysis Pentose phosphate shunt Gluconeogenesis Glycogenolysis, glycogenesis Galactose and fructose metabolism Glycogen storage disease Inborn errors of glucose metabolism - PowerPoint PPT Presentation

Text of Digestion and absorption of dietary carbohydrates Pathways of glucose metabolism: glycolysis

  • Digestion and absorption of dietary carbohydratesPathways of glucose metabolism: glycolysisPentose phosphate shuntGluconeogenesisGlycogenolysis, glycogenesisGalactose and fructose metabolismGlycogen storage diseaseInborn errors of glucose metabolismRegulation of glucose metabolism.

    Digestion and absorption of dietary fats.Biosynthesis and degradation of fatty acids, phospolipids and triacylglycerolsBiosynthesis of cholesterol, chemistry and metabolism of lipoproteins.HyperlipoproteinemiasLipid storage disease.Ketone bodies: their synthesis, utilization and conditions leading to ketoacidosis, general concepts and characteristics of metabolic pathways.III-I MetabolismIII-II Carbohydrate metabolismIII-III Lipid metabolismIII-IV TCA cycle and biological oxidationIII-V Protein turnover and amino acid metabolismIII-VI Regulation of the metabolic pathways(a) Digestion and absorption of dietary protein(b) General reactions, transamination, its metabolic and diagnostic significance(c) Disposal of amino acid nitrogen and detoxication of urea(d) Metabolic fate of amino acid carbon skeleton(e) Sulphur containing amino acids(f) In born errors of branched chain and aromatic amino acids(g) Important amino acid derivatives.(a) Interlinks between carbohydrate, lipid and amino acid metabolic pathways.(b )Cellular compartment and cooperation(c) Organ interrelationships in metabolism,(d) Metabolic adaptation in the fed state, fasting and prolonged starvation.(e) Blood glucose regulation, and its impairment in diabetes mellitus.(f) Metabolic derangements and adaptations in diabetes mellitus.

  • III-II Carbohydrate metabolismIII-III Lipid metabolismIII-V Protein turnover and amino acid metabolismIII-IV TCA cycle and biological oxidationIII-VI Regulation of the metabolic pathwaysIII-I MetabolismReview and Summarize

  • Interlinks between carbohydrate, lipid and amino acid metabolic pathways.Cellular compartment and cooperationOrgan interrelationships in metabolism,Hormonal control of fuel metabolismMetabolic adaptation in the fed state, fasting and prolonged starvation.Blood glucose regulation, and its impairment in diabetes mellitus.Metabolic derangements and adaptations in diabetes mellitus. III-VI Regulation of the metabolic pathways

  • Key intermediates connect pathways.Energy-rich compounds are converted mutually to a great extent.Carbohydrate/fat are priority-ranked in mobilizing.Key enzymes in pathways are regulated in similar way.Energy charge regulates whole status of metabolism.

  • The major pathways of fuel metabolism in mammalsOnly a few tissues, such as liver, can carry out all the reactions illustrated above.

  • metabolic pathways for glucose-6-phosphate in the liver

  • Summary of metabolic fates of pyruvateamino acidsamino acids

  • Overview of metabolism

  • Important reactions of intermediary metabolism regulated by phosphorylation of enzyme

  • Many reactions in metabolism are controlled by the energy status of the cell. High concentrations of ATP inhibit the relative rates of a typical ATP-generating (catabolic) pathway and simulate the typical ATP-utilizing (anabolic) pathways

  • Interlinks between carbohydrate, lipid and amino acid metabolic pathways.Cellular compartment and cooperationOrgan interrelationships in metabolism,Hormonal control of fuel metabolismMetabolic adaptation in the fed state, fasting and prolonged starvation.Blood glucose regulation, and its impairment in diabetes mellitus.Metabolic derangements and adaptations in diabetes mellitus. III-VI Regulation of the metabolic pathways

  • Molecules are transported between subcellular parts according to the demandPathways are located in different places in the cell.

  • urea cycleTCAglycolysismitochondriacytosol-oxidationfatty acid synthesisglycogen synthesisgluconeogenesispentose phosphate pathwayketone bodiesaerobic oxidation of carbohydrateprotein degradationlysosomeamino acids catabolismprotein degradationendoplasmic reticulum

  • Transfer of the starting materials of lipid anabolism from the mitochondrion to the cytosol.

  • Transfer of the starting materials of gluconeogenesis from the mitochondrion to the cytosol. 1.PEP carboxykinase in mitochondrion2.PEP carboxykinase in cytosol

  • Interlinks between carbohydrate, lipid and amino acid metabolic pathways.Cellular compartment and cooperationOrgan interrelationships in metabolism,Hormonal control of fuel metabolismMetabolic adaptation in the fed state, fasting and prolonged starvation.Blood glucose regulation, and its impairment in diabetes mellitus.Metabolic derangements and adaptations in diabetes mellitus. III-VI Regulation of the metabolic pathways

  • Tissues specific metabolismMetabolism is cooperated between tissues.Only a few tissues, such as liver, can carry out all the reactions illustrated in slide 7.

  • Specialized metabolic functions of mammalian tissuesLow blood glucose will result in brain dysfunction.Mitochondria occupy up to 40% of cytoplasmic space. atherosclerosis , insufficient O2 supply.Bodys central metabolic clearinghouse

  • the major fuel-metabolizing organs

  • Artery & Vein

  • The portal vein drains almost all of the blood from the digestive tract and empties directly into the liver. This circulation of nutrient-rich blood between the gut and liver is called the portal circulation. It enables the liver to remove any harmfulsubstances that may have been digested before the blood enters the main blood circulation around the bodythe systemic circulation.The portal circulationBodys central metabolic clearinghouse

  • There are two cycles between muscle and liver.

  • The Cori Cycle

  • The Glucose-Ala Cycle

  • Mechanisms of communication between four major tissues

  • Interlinks between carbohydrate, lipid and amino acid metabolic pathways.Cellular compartment and cooperationOrgan interrelationships in metabolism,Hormonal control of fuel metabolismMetabolic adaptation in the fed state, fasting and prolonged starvation.Blood glucose regulation, and its impairment in diabetes mellitus.Metabolic derangements and adaptations in diabetes mellitus. III-VI Regulation of the metabolic pathways

  • Living things coordinate their activities at every level of their organization through complex signaling systems involving chemical messengers known as hormones.In higher animals, endocrine glands synthesize and release hormones, which are carried by the bloodstream to their target cells. The human endocrine systems secretes a wide variety of hormones that enable the body tomaintain homeostasis, respond to wide variety of external stimuli , follow various cyclic and developmental programs

  • Endocrine signaling

  • Opposing actions of insulin and glucogon plus epinephrine

  • Insulin causes anincrease in glucose uptake, mainly in muscle cells and adipocytes, stimulates storage of glucose as glycogen, mainly in liver cells.

  • Glucagon acts mainly on liver cells to stimulate glycogen degradation.

  • Interlinks between carbohydrate, lipid and amino acid metabolic pathways.Cellular compartment and cooperationOrgan interrelationships in metabolism,Hormonal control of fuel metabolismMetabolic adaptation in the fed state, fasting and prolonged starvation.Blood glucose regulation, and its impairment in diabetes mellitus.Metabolic derangements and adaptations in diabetes mellitus. III-VI Regulation of the metabolic pathways

  • Feed/Fast largely effect the energy metabolism in different organs. The hormones will respond to the blood glucose and then regulate by their own ways.

  • Intertissues relationships in the absorptive stateInsulin-dependent transport system

  • Intertissue relationship during starvation

  • starvationabsorbtive

  • starvationabsorbtive

  • starvationabsorbtive

  • starvationabsorbtive

  • Key concept map for feed/fast cycle

  • Interlinks between Carbohydrate, lipid and amino acid metabolism pathways.Cellular compartment and cooperationOrgan interrelationships in metabolism,Hormonal control of fuel metabolismMetabolic adaptation in the fed state, fasting and prolonged starvation.Blood glucose regulation, and its impairment in diabetes mellitus.Metabolic derangements and adaptations in diabetes mellitus. III-VI Regulation of the metabolic pathways

  • Blood glucose levels are not constantthey rise and fall depending on the body's needs, regulated by hormones. This results in glucose levels normally ranging from 70 to 110 mg/dl. The blood glucose level can rise for three reasons: diet, breakdown of glycogen, or through hepatic synthesis of glucose. Eating produces a rise in blood glucose, the extent of which depends on a number of factors such as the amount and the type of carbohydrate eaten, the rate of digestion, and the rate of absorption.

    Regulation of Blood Glucose

  • The liver is a major producer of glucose it releases glucose from the breakdown of glycogen and also makes glucose from intermediates of carbohydrate, protein, and fat metabolism.

    The liver is also a major consumer of glucose and can buffer glucose levels. It receives glucose-rich blood directly from the digestive tract via the portal vein. The liver quickly removes large amounts of glucose from the circulation so that even after a meal, the blood glucose levels rarely rise above 110 mg/dl in a non-diabetic.

  • Glucose ho