Last time, we had a quick look at the problem of performance anxiety. This produces just as serious a dysfunction as the physical causes, but the use of Viagra, Cialis or Levitra is almost certainly indicated as the first-choice treatment and that use is more or less guaranteed to restore you to norm. Before we go on to some of those physical cases, we ought to get to know a little more about the mechanics of an erection. That’s the best way to understand what the drugs do and how other treatments can help. al sexual power

Would that this could be glamorous. But, sadly, there’s nothing magical or mysterious about an erection. It’s just a simple matter of plumbing or, if you prefer to give it a slightly better sounding profession, hydraulic engineering. Yes, we’re going to be looking at how liquids flow, why pressure directs and pumps, and getting an overall insight into liquid traffic management.

In design terms, we have to redefine our view of the penis. When we’re younger and exploring the world, it seems that the idea of sex dominates our lives. But the design actually places the penis as a backwater cul-de-sac. We have the main flow of blood going full bore round the veins and arteries, doing all that clever stuff about carrying oxygen to the right bits, and carbon dioxide away for disposal (isn’t it great to be scientific about these things?). Now think of ordinary river systems. They build from little tributaries to larger streams to rivers. Well, the body is exactly the same. As you go down a river, you’ll sometimes see very small openings off the main flow that don’t go anywhere. The currents are sluggish and almost no water goes in - just enough to keep that bit of the bank wet. Well, that’s the penis. The blood doesn’t have anywhere to go after filtering through the narrow opening, so not much blood goes in and leaves the whole thing flaccid - the fancy word for limp.

Now comes the exciting bit (both literally and metaphorically. When you’re sexually stimulated, this turns a little switch in the chemical production division (sex drive). There is then a cascading process:

on demand, nitric oxide is released;

this nitric oxide triggers the production an enzyme called guanylate cyclase (GMP);

in turn, GMP generates cyclic guanosine monophosphate (cGMP).

This mixture is pumped into:

the muscle cells in the walls of the arteries and veins carrying blood into and out of the penis; and

the network of blood vessels forming the corpus cavernosum - a sponge-like area of tissue inside the penis that is designed absorb an inflow of blood and so create the erection.

The brew of NO and associated letters relaxes the arteries and allows more blood to flow into the corpus cavernosum where it is absorbed. Because the veins are slower to enlarge, the blood cannot escape as quickly as it comes in. Pressure builds inside the penis and this creates a tumescence - you swell up like you’re going to explode (not too prematurely, we hope).

But if the body also produces phosphodiesterase type 5 (PDE5), this whole process may be slowed or stopped. And this is where Viagra, Cialis and Levitra come in handy because they stop the body from producing PDE5 - clever stuff. So the blood should flow naturally and produce the erection. It’s simple hydraulics.

Now we have this more intimate information out of the way, we’ll turn to looking at some of the physical causes of ED, and explain why you sometimes have to combine taking Viagra, Cialis or Levitra with out treatment.