A-V Difference and Fick Principle cardiac output- Vo/(A-V difference) Calculate

Question

A-V Difference and Fick Principle cardiac output- Vo/(A-V difference) Calculate the cardiac output (CO) for a specific individual at rest knowing: Vo2-0.25 L O2-min O2 content of arterial blood- 200 mL O2-L blood O2 content of venous blood-150 mL O2-L blood 2 S 200-1502S 0.005 L blood min If heart rate for this individual at rest is 62 beats-min, what is the stroke volume (SV)? sv = mL blood-beat Suppose for the individual in this example that oxygen consumption is increased from 0.25 to 2.8 L Op-min during exercise and that cardiac output increases to 20 L blood-min", but the arterial blood O content is unchanged. How will the oxygen content of the venous blood change? venous blood Oz contentml Calculate the value for O2 extraction from the blood (as a fraction or %) for these two conditions (namely, at rest and during exercise). 02 extraction at rest- O2 extraction during exercise- What effect(s) do you think exercise will have on heart rate and stroke volume?

Explanation / Answer

acording to fick's principle :

CO=VO2/(CAO2-CVO2)(Cardic output depends upon O2 consumption and diffrence of Oxygen content of atrial blood and venous blood.)

Here.

CO=20 Lblood/min

VO2=2.8 L O2/min

CAO2=200 ml O2 L/blood

Thus (200-CVO2)=2.8/20

200-CVO2 = 0.14

CVO2=200-0.14=199.86 ml O2 /L blood

Oxygen extraction ratio = global oxygen consumption(CAO2-CVO2)/global oxygen ndelivery(CAO2)

During exercise , there is a great demand placed on many aspets of the body(eg.Regulate body temperature,maintain body fluids,transport nutrient waste material etc.) as  working muscles require more oxygen and nutrients than normal, they produce more waste products and generate more heat. So the intense the body activity ,more intense the demand .

Our heart responds to exercise by increasing the heart rate in a linear fashion to increases in the intensity of exercise. and continous rise Stroke volume which is due to a greater volume of blood returning to the heart.    However stroke volume only continues up to a point. Since cardiac output is the product of heart rate and stroke volume, cardiac output also increases considerably .

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