The Ultimate Viagra Quiz

By: Staff
Image: refer to hsw

About This Quiz

Lots of rumors go around about Viagra, but what does this medicine actually do inside the body? Take the Viagra Quiz to see what you know about that little blue pill.

How does a penis become erect?

The process is a lot like blowing up a balloon, but instead of air, the penis becomes erect when its two cigar-shaped tubes called corpora cavernosa (singular: corpus cavernosum) fill with pressurized blood.

How does the blood flow to the penis change during an erection?

When a man becomes aroused sexually, the arteries in his penis expand and the veins contract. This leads to a net gain of blood -- and an erection.

The first drug developed to treat erectile dysfunction was called phentolamine. How was it originally demonstrated?

In front of urologists attending the 1983 American Urological Association Meeting, Dr. Giles Brindley did indeed drop his pants after injecting his penis with phentolamine. The first-ever, drug-induced erection wowed the crowd, and proved that erectile dysfunction is not primarily all in the head.

What were the down sides of phentolamine that lead to further research in treating erectile dysfunction and the development of Viagra?

Although many men did take advantage of phentolamine to ease their erectile woes, researchers continued looking for a drug that could be ingested in pill form -- and that offered a little more finesse and control.

Let's get back to the arteries and veins in the penis. Under normal circumstances, how do they know when to expand and contract?

As long as a man is aroused, his brain will continue triggering this simple chemical reaction that acts like an on/off valve. Nerve endings in the penis' corpora cavernosa receive signals to release nitric oxide, nearby enzymes react by producing cGMP (cyclic guanosine monophosphate), and this chemical tells the smooth muscles in the artery walls to relax and expand.

So what happens during erectile dysfunction?

Although lots of factors can cause or contribute to erectile dysfunction, the most common culprit -- especially in older men -- is that the arteries in the corpora cavernosa aren't making and sustaining enough cGMP to produce a full, rigid erection, even though the nerves in the penis are churning out plenty of nitric oxide.

How does Viagra work to treat this problem?

Viagra works by temporarily eliminating the PDE. This way more cGMP is allowed to build up, the artery walls dilate more fully and more blood can flow into the erection. But there's a little more to it than that…

There's PDE in other areas of the body too -- how does Viagra get around that?

Without the discovery that PDE5 is unique to the penis, we wouldn't have Viagra today. Pfizer, the maker of Viagra, took advantage of that fact by developing a chemical that specifically targets PDE5.

How does Viagra temporarily take out PDE5?

PDE5 is an enzyme with receptors specially suited to receive cGMP. So after a man takes a Viagra, the active chemical in the pill, sildenafil citrate, filters throughout his body until it reaches a PDE5 enzyme. There, it slots into the place cGMP would normally occupy, and the enzyme is disabled. When a man becomes sexually aroused, the regular process starts up, but this time, the penis is more capable of filling with blood and --ta-da! -- a full erection is achieved.

It's not all blue skies after that -- what's arguably the weirdest side effect that can come from popping back a few Viagra?

All right, those three are all pretty weird. Priapism (an erection lasting longer than six hours), cyanopsia (blue-tinted vision) and hearing loss are among some of the weirder side effects of Viagra, but there's lots more on the list -- many of them quite serious. So as the commercials always say -- check with a doctor before taking any prescription medication.

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