Pressure, Velocity, Fluids :?

[vayntraubinator]

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605) Blood is a viscous fluid. Assuming the heart supplies all the force to push the blood through the circulatory system, and ignoring the effects of gravity, where is pressure likely to be the lowest?
a) aorta
b) capillaries
c) Small Veins
d) Venae Cavae

607) If the blood behaves ideally, where would the pressure be the greatest?
a) aorta
b) capillaries
c) Small Veins
d) Venae Cavae

The answers to these two questions seem to oppose each other's rationale. According to EK, #605 the answer is d, Venae Cavae, since the similar Ohm's law (v=ir) for fluids is deltaP=QR, and by the end of the bloods trip, delta P will be greatest.

However, using this logic you'd think the Pressure would be greatest at the Aorta. I mean blood squirts out of this thing @ 30m/s. That's seems intuitive also with regards to P=QR. However, the answer is capillaries since the velocity is lowest here. Meaning that smaller velocity, hence less uniform Kinetic Energy, more Random Kinetic Energy, and a Higher pressure.

So does the equation (delta)P=QR no apply to ideal fluids?

 

[HelloNicky]

I think you have to consider the width of the aorta, capillaries, venae cavae, and small veins. Think about it this way. If you are cooking a pot of boiling water with the lid slightly open, the steam coming out have greater pressure than a pot of boiling water with no lid.