Your videos albeit are helpful but they're so long-winded, repetitive and not succinct enough especially when i'm under stress and want to understand a concept faster than having to watch 4 parts/1 hour, as a med student i just don't have the time to listen to you say 'basically' 987 times this could have been 30 minutes easily. Nonetheless, you did clarify some points so thank you. Apologies if this comes across as blunt, i'm extremely stressed at the moment :)
I think the gene names like frizzled, disheveled and smoothened came from the gene names given in Drosophila. I think these genes were discovered to be associated with various fruit-fly phenotypes that looked, for example, disheveled. There is a wikipedia article on the hedgehog pathway that discusses this https://en.wikipedia.org/wiki/Hedgehog_signaling_pathway
The class of drugs that Levitra, Viagra, Stendra, and Cialis belong to are called PDE5 inhibitors. They work by relaxing tight blood vessels, allowing more blood to surge into the penis and cause an erection, says Gregory Bales, M.D., an associate professor of urology at the University of Chicago.
The little pills do the trick for more than two-thirds of men with Viagra protects the heart (ED). They also work for guys who simply need them for a short time to get their “confidence back,” says Michael Eisenberg, M.D., director of male reproductive medicine and surgery at Stanford University.