BIOFISIKA ~ Bio Termofisika

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  • BIOFISIKABIO-TERMOFISIKAPENGATURAN SUHU TUBUHCooling the body D E M A MSensor Perubahan Suhu pada Mahluk HidupPENCITRAAN SUHUMETABOLISME TUBUH

  • REVIEW: SIFAT TERMAL BENDA ~ PANAS/DINGINhot and cold are only a sensation that we can feel (mostly by touching it)how hot or cold an object is described by term called temperaturetemperature is quantification of how hot or cold an object isTemperature is being measured using thermometer. Familiar thermometers are celcius, fahrenheit and Kelvin

  • REVIEW: SIFAT TERMAL BENDA ~ PEMUAIAN

  • http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/thexp2.html#c2REVIEW: SIFAT TERMAL BENDA ~ PEMUAIAN

  • REVIEW: SIFAT TERMAL BENDA ~ KALOR & PERPINDAHANNYA

  • REVIEW: SIFAT TERMAL BENDA ~ KALOR & PERPINDAHANNYAConductionSI Unit of Thermal Conductivity: J/(s m C)

  • Fouriers Law of Conduction

  • ConvectionREVIEW: SIFAT TERMAL BENDA ~ KALOR & PERPINDAHANNYAbreezes come from the ocean in the day and from the land at nightStyrofoam

  • Black Body RadiationREVIEW: SIFAT TERMAL BENDA ~ KALOR & PERPINDAHANNYAThe StefanBOLTZMANN Law Of Radiation = 5.67 .10-8 W/m2.K4.

  • Absorbing Solar Radiation Qabs = S A vfs aRate of absorption of solar energy depends on:The intensity of the radiation (S)Surface area of the animal (A)Proportion of the animals surface that is exposed to the radiation (vfs)Absorptivity, proportion of the energy that is absorbed rather than reflected (a)Herps have substantial control over the amount of solar radiation they absorb

  • Absorbing Solar Radiation Move between sun and shadeChange the amount of surface area exposed to the sunChange orientation to the sunChange color (albedo) to change absorptivityConcentrate pigments in melanophores to expose reflective pigments and cast off light. Disperse melanin to absorb light

  • Thermos BottleStopper- minimize conduction.Double-walled glass vessel with the space between the walls is evacuated to minimize energy losses due to conduction and convection.The silvered surfaces reflect most of the radiant energy that would otherwise enter or leave the liquid in the thermos. A thermos bottle minimizes energy transfer due to convection, conduction, and radiation

  • PENGATURAN SUHU TUBUHMekanisme perpindahan kalor berpengaruh pada pengaturan suhu tubuhhttp://www.colorado.edu/intphys/Class/IPHY3430-200/021metabolism-energy.htmHomeostasis Control PrinciplesHomeostasis is the maintenance of a relatively constant state in a system where the state can change.

    Set point - the desired level of a state that is to be maintained.

    Negative Feedback Control - the most common control system used to achieve homeostasis.

  • For an endothermic homeotherm to control body temperature at a constant level:

    Heat production rate (H) must balance heat loss rate (Q).PENGATURAN SUHU TUBUH: Linear Heat Transfer Equation

  • Thermal Neutral ZoneTLCTUCHeat ProductionTLC = Lower critical temperature; TUC = Upper critical temperature

    Chart1

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    Temperature

    Body Temperature, oC

    Sheet1

    AmbientBody

    TemperatureTemperature

    037.6

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    Ambient TempMet. RateExtrap.

    0

    23.34

    33.39

    43.367

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    Temperature

    Body Temperature, oC

    Sheet2

    Met. Rate

    Extrap.

    Ambient Temperature, oC

    Metabolic Rate

    Sheet3

    Chart3

    00

    3.342

    3.393

    3.3674

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    Met. Rate

    Extrap.

    Ambient Temperature, oC

    Metabolic Rate

    Sheet1

    AmbientBody

    TemperatureTemperature

    037.6

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    4138.4

    Ambient TempMet. RateExtrap.

    0

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    Sheet1

    0

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    Met. Rate

    Extrap.

    Ambient Temperature, oC

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    Sheet3

  • Within the Thermal Neutral Zone, heat loss is controlled by changing conductance (C).H = Q = C (TB - TA)Thermal Neutral Zone

    Chart3

    00

    3.342

    3.393

    3.3674

    38

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    1.541

    281

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    Met. Rate

    Extrap.

    Ambient Temperature, oC

    Metabolic Rate

    Sheet1

    AmbientBody

    TemperatureTemperature

    037.6

    237.9

    438

    638

    838

    1038

    2038

    3038

    3538

    3838.1

    4038.2

    4138.4

    Ambient TempMet. RateExtrap.

    0

    23.34

    33.39

    43.367

    83

    281

    381

    411.5

    281

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    Sheet1

    0

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    Body Temperature, oC

    Sheet2

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    Met. Rate

    Extrap.

    Ambient Temperature, oC

    Metabolic Rate

    Sheet3

  • Erection of hairs or feathers to increase thickness of the body surface covering. Control of blood flow to the body surface. Blood vessels can constrict to slow blood flow to a specific region. PENGATURAN SUHU TUBUH MANUSIA: Adjusment of Insulation

  • Heat Conduction to the Skin The skin and the subcutaneous tissues especially the fat form a heat insulator system for the body. This system maintains the normal core temp., although the temp. of the skin may approach the temp.of the surrounding.Blood vessels penetrate the fatty subcutaneous tissues and are distribution beneath the skin. The amount of heat reaching the skin from the deep tissues depends upon the blood flow into the cutaneous blood vessels which is determined by the degree of vasoconstriction of the vessels.This vasoconstriction in turn is controlled almost entirely by the sympathetic nervous system.The rate of heat conduction to the skin is known as tissue conductance.

  • Heat loss from the skin surfaceRadiation Human body radiates heat rays in all directions but is also exposed to heat rays radiated from the surrounding. Therefore, heat is lost by this method when the temp. of the surrounding is less than the body temp. At normal temp. about 60% of the total heat loss from a nude person occurs by radiation.Conduction Only minute amount of heat are normally lost from the body by direct conduction to other objects such as a chair or bed (3%). On the other hand large amounts of heat are lost by conduction to air. Convection It is the removal of heat from the body by convection air currents.Heat must first be conducted to the air and then carried away by the convection current.About 12% of heat loss from the body occurs by conduction to the air and then by convection.When the body is exposed to wind heat loss by convection is greatly increased.

  • Heat loss from the skin surfaceEvaporation Evaporation of 1g water removes about 0.6 Kcal. Of heat. Even when a person is not sweating a certain amount of water still evaporates from the skin and lungs at a rate of about 600 ml/day. This is known as the insensible water loss. Sweating provides a very important way of heat loss from the body which can be regulated. As long as skin temp. is greater than the temp. of surrounding, heat can be lost by radiation & conduction, but when the temp. of the body gains heat by radiation& conduction..Urine & Feces Small amount of heat are removed

  • PENGATURAN SUHU TUBUH MANUSIA: Adjusment of Insulation

  • Shivering Thermogenesis:High frequency, uncoordinated contractions of opposing skeletal muscles.Nonshivering Thermogenesis:Elevated metabolic rate in many tissues releases heat, especially in brown adipose tissue (brown fat). PENGATURAN SUHU TUBUH: Mechanisms of Heat Production

  • PENGATURAN SUHU TUBUH: Brown Adipose tissue Heat Generation

  • Cooling of the Human BodyHm = Hc + Hr + Hs + HlHm = kalor dr metabolime (70 1400 kkal/h)HC = kalor hilang konveksi = 6,1 A (Ts Ta) kkal/hHr = kalor hilang radiasi = 5,6 A (Ts Ta) kkal/hHs = kalor hilang evaporasi keringat = 580r kkal/h Hl = kalor hilang evaporasi dr paru-paru = 9 kkal/hA = luas bidang tubuhTs = suhu kulit ; Ta = suhu udarar = laju keringat (kg/h)

  • The cooling effect of perspiration evaporation makes use of the very large heat of vaporization of water. This heat of vaporization is 540 calories/gm at the boiling point, but is even larger, 580 cal/gm, at the normal skin temperature. http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/coobod.html#c1Simplified model of the process by which the human body gives off heat. Even when inactive, an adult male must lose heat at a rate of about 90 watts as a result of his basal metabolism.

  • Cooling of the Human Body Newtons Law of Cooling. . . . . . .

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