Physiology 3120 Lecture Notes - Hemoglobin, Partial Pressure, Carbonic Anhydrase

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26 Nov 2011

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Oxygen transport: transported (i) as a dissolved gas (minor component), or (ii) bound to haemoglobin, binding to haemoglobin. 4 subunits, each with heme group (has an iron molecule to which o can bind) O capacity of blood perform experiment; have blood equilibrate and measure the amount bound to h. In the lung, the h saturation is almost 100% (at 100mmhg) If the po drops in the lung, still have high saturation (at 60mmhg, saturation is still 90% or so); not a linear curve. Po in tissue is low, and there is a steep drop in affinity, which allows dissociation of o in tissues. Shape is sigmoidal ; results from binding of h to o; binding one o molecule is hard, but once it binds, the other 3 o"s can bind relatively easily. Co has 210-fold higher affinity for h than o these 3 in terms of exercise. If you have po of 210mmhg, then 100% bound to h.

Related Questions

A "pulse oximeter" operates by using light and a photocell tomeasure oxygen saturation in arterial blood. The transmission oflight energy as it passes through a solution of light-absorbingmolecules is described by the Beer-Lambert law, given below, whichgives the decrease in intensity I in terms of the distance L thelight has traveled through a fluid with a concentration C of thelight-absorbing molecule.
I = I010-eCL or log10(I / I0) = -eCL
The quantity e is called the extinction coefficient, and its valuedepends on the frequency of the light. (It has units of m2/mol.)Assume the extinction coefficient for 660-nm light passing througha solution of oxygenated hemoglobin is identical to the coefficientfor 940-nm light passing through deoxygenated hemoglobin. Alsoassume also that 940-nm light has zero absorption (e = 0) inoxygenated hemoglobin and 660 nm light has zero absorption indeoxygenated hemoglobin. If 30% of the energy of the red source and79% of the infrared energy is transmitted through the blood, whatis the fraction of hemoglobin that is oxygenated?

%???

I =I₀10^-ÎµCLorlog₁₀(I / I₀)=-ÎµCL

The quantity Îµ is called the extinctioncoefficient, andits value depends on the frequency of the light.(It has units ofm²/mol.) Assume that the extinctioncoefficient for 660nm light passing through a solution ofoxygenated hemoglobin isidentical to the coefficient for 940 nmlight passing throughdeoxygenated hemoglobin. Assume also that 940nm light has zeroabsorption (Îµ = 0) inoxygenated hemoglobin and 660 nmlight has zero absorption indeoxygenated hemoglobin. If 31% oftheenergy of the red source and 78% of theinfrared energy istransmitted through the blood, determine thefraction of hemoglobinthat is oxygenated.

Your response is within 10% of the correctvalue. This may be due toroundoff error, or you could have amistake in your calculation.Carry out all intermediate results toat least four-digit accuracyto minimize roundofferror.%

I was usingthis as a guide but I get the same answer anditswrong:/answers-mar-09/physics/urgent-need-help-please-a-pulse-oximeter-operates-by-using-light-and-a-photocell-to_514319.aspx

Consider a refrigeration cycle using r-134a to maintain temperatureof blood storage space at -15 degrees C. The cycle consists of foursteady flow components.

R-134a passes through an evaporator (a heat exchanger) removingheat from the refrigerated storage space such that it exits theevaporator as saturated vapor at -20 degrees C. (State 1)

The refrigerant then enters a compressor where it is compressed tosaturated vapor at 5 bar. (State 2)

After exiting the compressor, R-134a enters a condenser (anotherheat exchanger) where it rejects heat to surrounding air at 10degrees C and exits as a saturated liquid at 5 bar. (State 3)

The refrigerant exiting the condenser passes through a throttlingvalve so that its pressure drops before entering the evaporator(state 4).

The mass flow rate of R-134a is 3kg/min.

(a) Draw a diagram showing all the components of the refrigerationcycle labeling all relevant states. Sketch another schematicshowing the refrigeration cycle and all its energy interactionswith surroundings.
(b)What capacity (kW) compressor is required to operate thecycle?
(c)Determine the specific volume of R-134a at the exit of theexpansion valve (or inlet to the evaporator)
(d)Calculate the CPO of the refrigeration cycle

Physiology 3120 Lecture Notes - Hemoglobin, Partial Pressure, Carbonic Anhydrase

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