How does the mental thing during a sexual arousal work ?
When a person becomes aroused in the brain, signals travel down the spinal cord to the ganglia in question, activating special autonomic nerves. When these nerves are activated, they tell some very special arteries to open up. They do this by releasing some neurotransmitters that start a biochemical cascade, which results in the relaxation of the smooth muscle that ordinarily keeps these arteries tightly closed. Result: arteries open up, filling the cavernous bodies of the penis with blood and causing it to become erect. So you have an aroused brain and an erect penis, which are more or less the necessary ingredients for sex. Viagra and Cialis either Generic or Original come in in the middle of that cascade and just sort of switches the whole deal on. Result: Brain is aroused, nerves are silent because the surgeon damaged them, but the arteries open up, the penis becomes erect anyway. So you have, again, an aroused brain and an erect penis.
