Pudendum, I appreciate your knowledge of erectile physiology. I don’t pretend to know that much about it and don’t intend to question what you say. You provide good references. Blood flow in the penis during erection is apparently very low, or zero, but there is a big difference between zero, as stated in your first reference, and almost zero, as stated in your second.
Sure the penis can withstand low oxygen for “some time” but how much time is that? How much flow is almost no flow? I would guess that even very miniscule flow through the penis during marathon sex can do a lot to prevent oxygen deprivation.
I am not sure how you can say there is a difference between a filled balloon and the penis as far as response to negative pressure at peak erection
Well, you answer your own question in your next sentence.
(I will grant you that up to this point, blood is drawn into the penis by the negative pressure; this is what made it good for guys with ED).
There you go. That doesn’t happen with the balloon. Actually it is more accurate to say that blood is forced into the penis by the heart, facilitated by less external pressure on the tissue, allowing it to expand.
Again at peak erection, the penis is exactly like the balloon, an isolated system, Therefore the effects depend on compliance, not inflow or outflow. Remember, I’m talking about peak erection.
I would modify your statement as follows:
Again at peak erection, the penis is not exactly like the balloon, not an isolated system, because the effects (of vacuum) depend on compliance (of the penile tissue), as well as externally applied pressure on the internal fluid in the case of the penis, but not the balloon, Even if there is not inflow or outflow. Remember, I’m talking about peak erection.
Look at it this way: you connect a hose with 60 psi water pressure to a metal tank. there is a pipe on top of the tank with a valve on it. You fill the tank until water is coming out of the pipe, then shut the valve.
The water is still turned on, so there is 60 psi in the tank and hose, but there is no flow in or out.
Now, you magically turn the tank into a rubber walled tank that expands 5% due to the 60 pounds of pressure on it.
The tank has grown in size, water flowed to fill the additional space, then stopped when the system reached equilibrium. The pressure in the tank is still 60 pounds.
That is your penis.
Put a giant cylinder over this tank and pull a vacuum. The tank will grow more, water will flow into it, it will reach equilibrium, and the pressure will still be at 60 pounds.
The balloon full of water is much different:
Take the same example of the full tank.
This time you shut off the hose first with a valve at the tank where the hose connects to the tank. ( a knot in your balloon!)
Then you magically turn the walls in to rubber as before.
The tank grows due to the internal pressure, and as the tank grows, the pressure drops. It reaches equilibrium at some size smaller than the tank in example one, and the pressure is something less than the original 60 pounds.
Now put a giant cylinder over this tank and pull a vacuum. The tank will not grow more as in the first example.
The difference is the pump. The heart in your body, or the pump at your city water department. The balloon is a closed system, and the penis is not, because it is connected to your heart, even if there is no flow, there is pressure applied from the outside, just like that hose connected to the full and closed, tank.
Last edited by mravg : 01-03-2008 at .