I smoke. For some reason, I've always had this idea that the pleasure of smoking works more or less like this: from the lungs, the nicotine reaches the blood, with which it travels to the brain, and there it does some difficult chemical stuff to make me feel all good. But that's also never made sense to me. I mean, the gratification is instant. I don't even inhale very deeply, and, momentarily, I feel the feeling for which I do the thing. I don't know how fast the blood travels -- I only know it varies -- but it seems impossible for it to travel this fast. Or is it?
Could you explain to me, a non-biologist, how it works?