The Neurovascular Bundle

Both systems, parasympathetic and sympathetic, have an outflow and an inflow from the brain and to the brain. We share these with lizards and, I don't know about birds, but probably in some degree or another. And this is a universal feature of at least mammals. The exiting part of the system is what's been emphasized throughout the history of medicine. But they're very specifically organized in ways that sort of are counterintuitive, right?