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Kermut64 karma

I'm a med student studying for boards so this is good practice-

There are two things you need to understand to get how this works-

First is Eisenmenger's Syndrome (ES). ES consists primarily of a ventricular-septal defect, commonly called "a hole in the heart". The VSD occurs between the right and left ventricles of the heart, or the high-pressure parts of the heart. Normally the Left Ventricle (LV), which pumps blood to the body, is at a higher pressure than the Right Ventricle (RV). But when you have a hole between the two, the pressure will equalize. This is achieved by the LV pumping blood into the lower pressure RV, which then goes to the lungs (for a brief primer on cardiac blood flow go here: http://health.howstuffworks.com/human-body/systems/circulatory/heart3.htm).

With ES, after a number of years the RV will hypertrophy (increase in size) to compensate for the additional work being generated by the increased blood from the LV. Once this happens, the pressure of the RV increases. This in turns increases the pressure in the pulmonary arteries. The pulmonary arteries are NOT designed to accept high blood pressure, and as a result will become damaged and scar- this in turn increases the pressure, exacerbating the problem.

Viagra (Sildenafil) acts by inhibiting phosphodiesterase-5. Phosphodiesterase 5 dephosphorylates cyclic guanosine monophosphate (cGMP) to 5'-GMP. cGMP is a vasodilator, which means the blood vessels relax (reducing pressure per Poiseuille's equation).

While all blood vessels can dilate, they are controlled by different proteins. PDE5 is specific to to corpus cavernosum of the penis and to the pulmonary arteries. By inhibiting PDE5 in the pulmonary arteries, the goal is to keep the arteries dilated and minimize scarring/fibrosing of the pulmonary vasculature, minimizing the damage.

And as all of the other posters have noted, it also helps give you a raging boner.

Kermut10 karma

I’ve always wanted a Monster...but the Triumph sounds cool as well. Bikes are awesome.

I used to ride a Speed 4 but sold it because I didn’t have time to ride, now I drive a Miata and have a kid. I will say that around the time I quit riding texting/mobile internet had really gone mainstream (circa 2014 ish) and distracted drivers were just awful. Does that ever make you reconsider riding?

Kermut4 karma

You didn't have to post picture proof, the name Vern is enough to convince me you're a 96 year old man.

Teasing, thanks for your service!

Kermut0 karma

How bewildered are you by the anti-government sentiments right now?

I’m married to a Shanghainese woman and every time I’ve been to visit I’ve been impressed by the courtesy of my various hosts.