Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors
Arterial End of Capillary Bed Venous End of Capillary Bed
Hydrostatic Pressure 8 mm Hg 14 mm Hg
Osmotic pressure 26 mm Hg 26 mm Hg
PO2 100 mm Hg 42 mm Hg
PCO2 40 mm Hg 46 mm Hg
For this capillary bed, which of the following statements is correct
a) fluids will leave the capillaries on the arterial side of the bed and re-enter on the venous side
b) oxygen is taken up by the erythrocytes within the capillaries
d) the hydrostatic pressure declines from the arterial side of the venous side because oxygen is lost
e) the pH is lower on the arterial side than on the venous side
The site of this capillary bed could be all of the following except the
e) muscle tissue
There is a lot of information in these two questions that are intended to get the student lost in unnecessary data. The critical factor is the pO2 data. What does it tell us? It tells us that the partial pressure of O2 going into the capillary bed is 100 mm Hg and that the partial pressure of O2 leaving the capillary bed is only 42 mm Hg.
Therefore, let's focus on that. Oxygen is entering the capillaries and is being picked up by the ...