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Metabolismo

Metabolismo. Definición de metabolismo. Es la suma de todas las reacciones químicas que ocurren en un organismo La actividad metabólica de un animal se relaciona con su temperatura corporal ya que la velocidad de una reacción química aumenta con la temperatura. ALGUNAS DEFINICIONES.

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Metabolismo

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  1. Metabolismo

  2. Definición de metabolismo • Es la suma de todas las reacciones químicas que ocurren en un organismo • La actividad metabólica de un animal se relaciona con su temperatura corporal ya que la velocidad de una reacción química aumenta con la temperatura

  3. ALGUNAS DEFINICIONES CALORIMETRÍA Directa Indirecta Tasa Metabólica BASAL ESPECíFICA ACTIVA ESTÁNDAR Regulación hormonal y nerviosa b a es la ordenada al origen M la masa corporal b exponente empírico TMB = aM

  4. Lavoisier’s direct calorimeter • Direct calorimetry • Used in 1780

  5. An open respirometer

  6. A closed respirometer

  7. EJERCICIO Y DEUDA DE OXÍGENO

  8. METABOLISMO: Carbohidratos Monosacáridos (glucosa) Disacáridos (sacarosa) Polisacáridos (almidón) Glucogénesis y glucogenólisis en hígado Gluconeogénesis (deaminación proteica) Glucosa-6-P en músculo Glucostato hipotalámico Proteínas Metabolismo hepático Regulación hormonal Grasas Ésteres de AG con glicerol Lipólisis Transporte de quilomicron Metabolismo hepático Control neural y hormonal HDL y LDL

  9. Grasas 9 cal/g – 22% peso corporal – 84% valor combustible Proteínas 4 cal/g – 14% peso corporal – 15% valor combustible Carbohidratos 4 cal/g – 0,77% peso corporal – 1% valor cvombustible • OBESIDAD • >20-25% CONTENIDO DE GRASA EN EL CUERPO • Hipertrófica • Hiperblástica-hipertrófica • INANICIÓN • Carbohidratos • Grasas y proteínas • Proteínas estructurales

  10. ACCION DINAMICA ESPECIFICA

  11. ACCION DINAMICA ESPECIFICA

  12. RELACIÓN MASA-SUPERFICIE

  13. TMB y TAMAÑO CORPORAL I

  14. TMB y TAMAÑO CORPORAL II

  15. TMB y TAMAÑO CORPORAL III b TMB = aM

  16. TAMAÑO CORPORAL Y REQUERIMIENTOS ENERGÉTICOS

  17. TASA METABÓLICA ESPECÍFICA

  18. TASA METABÓLICA ACTIVA

  19. TEMPERATURA Transmisión de calor radiación conducción convección evaporación (transpiración, respiración) HOMO vs POIQUILOTERMIA ENDO vs EXOTERMIA Mecanismos termogénesis tiritante comportamiento grasa blanca / grasa parda circulación transpiración / jadeo piloerección control nervioso y hormonal

  20. Endotherms and Ectotherms • Endotherms- have constant body temperature (Tb) and maintain elevated Tb by endogenous heat production • High VO2, high heat production, low thermal conductivity (good insulation) • high metabolic cost, 5x metabolism of ectotherms • Mammals, birds some reptiles and insects

  21. Ectotherms or poikilotherms - thermal condition outside their bodies determine their Tb • - their Tb are high in warm environment, but low in cool environment • - they adjust Tb by means other than heat production and heat loss • Low VO2, low heat production, and poorly insulated • fish, reptiles and amphibians

  22. Homeotherms and Heterotherms Homeotherms – thermoregulate their Tb by physiological means, e.g. the rate of heat production, rather than just by behaviors - thermoregulation endotherms

  23. Heterotherms • Exhibit characteristics of endotherms and ectotherms. • Temporal heterotherms-hibernators, daily torpor in birds and mammals. Some snakes, fish, and insects. • Regional heterotherms-usually poikilotherm that maintains a high core temperature. Eg., bumble bee.

  24. Pigmy mouse Baiomys taylori

  25. Temperature relations in endotherms

  26. Thermodynamic Principles ENVIRONMENT Radiation Conduction Convection Evaporation ENVIRONMENT Radiation Conduction Convection HEATGAIN ANIMAL HEAT LOSS METABOLISM Maintenance Exercise Growth Lactation Feeding METABOLISM Milk Removal Fecal Removal Urinary Removal

  27. Heat Transfer Between Animals and • Their Environment • Conduction:transfer of heat between objects in • contact with each other • Convection:transfer of heat contained in a mass • of gas or liquid by the movement of that mass. • e.g wind • Radiation:transfer of heat by electromagnetic • radiation takes place without direct contact • between objects • Evaporation: transfer of heat by allowing water to • evaporate from moist body surface

  28. Thermal neutral zone • Range of Ta in which endotherm does not need to alter VO2 to maintain constant Tb. • Upper critical temperature (UCT)-Ta above which energy-requiring heat loss mechanisms are used- sweating, panting. • Lower critical temperature (LCT)- energy-requiring heat production mechanisms are used- shivering, non-shivering thermogenesis.

  29. Regulación en la zona termoneutral

  30. Countercurrent Heat Exchange • “opposite flow” • A process that depends on a specialized morphological arrangement of the blood vessels carrying blood to and from appendages • Transfer of heat between two closely juxtaposed fluid streams flowing in opposite directions • e.g. rete mirabile ---wonderful rete

  31. RETE MIRABILE en el Atún

  32. Q10 • Q10 is the rate of a reaction at a given temperature compared to its rate 10o C lower. • For most reactions, Q10 is 2-3X

  33. Acclimation • Laboratory-induced temperature acclimation in ectotherms. • Acclimation in whole animals occurs through the acclimation of individual cells and tissues.

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