BIO 203 Lecture Notes - Lecture 2: Blood Vessel, Thermal Conduction, Vasoconstriction
13 Jan 2016
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Lecture 2: body temperature & temperature regulation (chp 4 & 22) All life is constrained by the laws of physics and chemistry. Ohm"s law, boyle"s law, ideal gas law, gravity, kinetic & potential energy, inertia, Physical environment governs what cells can and can"t accomplish. Cells can utilize these laws to their advantage (e. g. signaling) Size principle - relationship between surface area (sa) and volume (v) The sa/v ratio is an index of relative surface area for exchange. Small animal vs large animal (consider small sphere vs large sphere) Sa / v prop (pi r^2) / (pi r^3) prop 1/r. Therefore, as radius gets bigger (i. e. , large animal) the sa/v ratio gets smaller and relative surface area for exchange decreases. Smaller animals will have a much harder time compared to larger animals to retain. All life can tolerate only a limited range of conditions.
