Spinal/Cranial Nerves/SNS vs ANS

Tuesday of this week we expanding on the Cranial and Spinal nerves. First we re-capped that the vetebral canal is where the spinal cord passes thorough the veterbral column. We looked at the break-down on different vertebrae: Cervical has 7, thoracic 12, lumbar 5 and sacrum 5. There are 31 spinal nerve pairs. It was interesting to learn that the cranial nerves come out superiorly from the vertebrea whereas the spinal nerves emerge inferiorly. We touched on the meninges, the spinal cord only has one layer whereas the brain has two. It's important to know anatomical names and positions we reviewed that anterior and ventral both mean the front and posterior and dorsal refers to the back. Sensory and motor neurons travel in opposite directions like a highway. Sensory output leaves posteriorly as motor output leaves anteriorly. The ascending tracts head toward the brain and carry sensory impulses. They are found on each side of the posterior fissure. They relay infor about proprioreception. The Gracius Fasiculos provides info from the lower legs to the brain while the Cuneanus fasiculu realys info from the upper extremities. The descending tracts travel down the spinal cord and carry motor impulses. The spinothalamic tract is so named that it tells you the impulse gets on at the spinal region and off at teh thalmus. It relays sensory of pain and temperature. The anterior corticospinal and lateral corticospinal tracts realy every impulse out to the entire body.
After reviewing and learning this information we were sent home with a take-home quiz. I spent every moment working on that, to the point that I was second-guessing my answers. There came a point when I just had to set the quiz down and walk away. Thursday we returned to lecture, went over some information about the cranial nerves that we hadn't yet learned and hesitantly passed in the quiz. Thursday we started talking about the parasympathetic and sympathetic nervous systems. I think it's easiest to remember that the sympathetic takes your body away from it's baseline while the Parasympathetic returns you to baseline. The Parasympathetic is also nick-named the "feed/breed" or rest/digest system with the Sympathetic is known for its "fight or flight" responses. We also talked about the muscles of the eye. The radial muscles are controlled by the SNS and they cause pupillary dilation. The circular muscles of the eye are controlled by the PNS and constrict the pupil.
Learning about all the cranial nerves reminded me of something. When I was much younger I had to have lower mandibular surgery. I remember my surgeon talking about the mandibular nerve. Even though I was young he took out the model of a skull and explained to me how my surgery would go, where the incisions were, the cutting of the mandible and where the nerve is in the jaw. He said that if it was damaged I could have permanent damage. In my case that didnt' happen but as I read stories from blotched surgies online it's unfortunate that so many people have to suffer through this. This goes to show how important every part of our bodies are and that we need to take charge of our own health an well being. We live in this body yet many of us know (or even care) about it. This A&P class has been so interesting because I have learned so much about my body. It's an amazing piece of work.