How does an erection occur and how does medication help?
Sexual excitement results in an increase of blood supply to the penis. Signals from the brain and spinal cord to the cells in the penis start the process off. Within the cells chemical processes occur that lead to muscle relaxation, valves opening and blood flow increasing. One of these pathways increases a chemical called cyclic GMP which triggers the increase in bloodflow. Drugs like Viagra, Cialis,and Levitra work by stopping the body mopping up Cyclic GMP hence blood flow increases and erection quality improves.
