I ALREADY HAVE PART A I JUST NEED PART B Lance Armstrong (fully doped) had a max

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I ALREADY HAVE PART A I JUST NEED PART B

Lance Armstrong (fully doped) had a maximum oxygen consumption output (VO2) of 5.5 liters O2/min. If during maximum exertion his arterial oxygen content is 20 mL/100 mL blood and his venous content is 2 mL/100 mL blood, a) calculate his cardiac output. In mammals in general, blood volume is equal to 7% of body mass (assume one litre of blood weighs 1.0 kg). If he weights 65 kg b) during this maximum exertion how long will it take to circulate his entire blood volume (i.e., how long for heart to pump his blood volume once?)

POTENTIALLYUSEFUL INFORMATION:
PV=nRT, one mole of STP gas occupies 22.4L. Saturation water vapor at 37 degrees Celsius is 47 mmHg, at 25 degrees Celsius is 24 mmHg and at -30 degrees Celsius is 0.4 mmHg. Atmospheric air is 21% O2. Sea level barometric pressure (Pb) is 760 mmHg. PAO2=0.21 (Pb-47) - PaCO2/RER (A=arterial, a=alveolar) Note RER = respiratory exchange ratio = CO2 produced/O2 consumed
normal value PaCO2=40 mmHg
Fick equation=VO2=CO(CaO2-CvO2) where CO=cardiac outout
Use textbook RER values for fat: 0.7, Protein: 0.8 and Carbs: 1

Explanation / Answer

Ans> From Fick equation we know that,

VO2 = CO (CaO2 - CaO2) where CO = Cardiac output ; VO2 = Volume of oxygen consumed per minute= 5.5 L/min ; CaO2 = concentration of oxygen in arterial blood = 20mL/100mL = 200mL/ 1L ;  CaO2 = concentration of oxygen in veneous blood = 2ml/100ml = 20mL/1L

Putting these values in the above equatio we get, CO = 5500ml/(200-20) = 30.55 L/min = cardiac output

Blood volume = 0.07 x 65 = 4.55kg = 4.55 L of blood.

b) During maximum exertion the time taken to circulate his entire blood volume is, (Blood Volume)/(CO) = 4.55/30.55 = 0.148 min = 8.88 seconds

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