 Hey everybody, Dr. O here. In this video we're going to talk about the organization, the anatomy of the parasympathetic nervous system and then in the next video we'll cover its activation and its function. So the parasympathetic nervous system is also called the cranial sacral division because it's controlled by cranial nerves 3, 7, 9, and 10 and the sacral segments S2 to S4. So cranial nerves 3, 7, 9, 10, that would be oculomotor, facial, glassoverein, pharyngeal and vagus. So cranial nerves 3, 7, and 9 are going to control the head. Cranial nerve 10 controls the neck and your thoracic and abdominal pelvic cavity and then the sacral nerves take over for the reproductive system and the lower portion of the abdominal pelvic cavity there. So that's kind of the anatomy of it. Remember from our intro video that the preganglionic fibers are going to be really long. So see all those blue fibers travel almost all the way to the organ and then the postganglionic fibers are going to be short. So why does that matter? That means there's very little divergence. So the responses are going to be under much more local control whereas the sympathetic system causes these huge, diffuse, you know, broad effects. The parasympathetic nervous system like a single nerve might only control just a half dozen or so synapses there. So the controls are going to be a lot more specific and a lot more localized. The fight or flight system takes over your entire body. The parasympathetic nervous system is only going to be controlling specific areas and its primary function is going to be to stimulate organs, visceral activity versus everything else, right? So a real big picture before we jump into it in the next video. The parasympathetic nervous system conserves energy and helps with, you know, it actually promotes sedentary activities like digestion and urine production, these kind of things. All right, that's the organization of the system there. We covered the synapses or the neurotransmitters in a different video. We'll come back and talk about the function of the parasympathetic nervous system next. Have a wonderful day. Be blessed.