The physiological mechanisms behind erections, focusing on the roles of the endothelium, cyclic guanosine monophosphate (cGMP), and phosphodiesterase type 5 (PDE5). It details how nitric oxide, released by the endothelium, activates cGMP to relax penile arteries, enabling erections, while PDE5 breaks down cGMP to end them. Erectile dysfunction arises from impaired endothelial function or excessive […]