Neuro Anatomy

Let’s review the Anatomy of the nervous system. Most of this is review, but we want to make sure you get these basics because it will help everything else fall into place.

So let’s talk macro anatomy – what are the main structures of the nervous system? In the Central Nervous system we have the brain and spinal cord – that’s the control center. Then in the Peripheral nervous system we have the ganglions coming off the spinal cord and the spinal and peripheral nerves. Then, we also have adjuncts that are found throughout the nervous system. The first is the meninges – these are the connective tissue layers around the brain and spinal cord. We’ll talk more about these when we talk about meningitis in a later lesson. And then there’s cerebrospinal fluid. This is found between the meninges and the brain and spinal cord as a cushion and a method for circulating nutrients throughout the central nervous system.

Now, I want to briefly talk about the cells. What’s most important here is that you understand that there are multiple types of nerve cells, or glial cells, and they all have a special purpose. The neuron is what we call the functional unit of the nervous system. This is the cell that is responsible for all nerve transmission. It’s the yellow one in this image. When we talk about impulse transmission, we’ll look a lot closer at the neuron. Then we have Oligodendroglia. These cells are responsible for creating the myelin sheath that surrounds and protects the axons of the neurons. They’re blue in this picture. Then there’s the microglia. These are responsible for phagocytosis – so if there’s any tissue damage within the nervous system, the microglia come to clean it up and phagocytize the dead tissue. Then there’s the astrocytes. They’re the green ones in this image. These cells are responsible for the blood-brain-barrier. You can see how they wrap around the blood vessels and act as a go-between between the vessels and the neurons. We’ll talk more about this in the blood-brain-barrier lesson, so be sure to check it out. Then, finally there’s the ependymal cells, these are responsible for lining the outside of the brain and creating CSF. So those are the main cells and their functions.

Now let’s quickly review the divisions of the nervous system because this will affect so many areas of nursing, including cardiac and pharmacology. So we know we have the CNS, which is the brain and spinal cord. Then we have the PNS or peripheral nervous system. This is divided into two main pathways – Sensory, or Afferent, and Motor, or Efferent. You can remember S.A.M.E. Sensory is for signals coming TO the brain, Motor is for signals FROM the brain to the body. Further dividing the Peripheral nervous system is the Autonomic and Somatic nervous systems. The Somatic nervous system works on voluntary actions, so it’s primarily motor. The autonomic is involuntary (think automatic) – it’s actually both sensory and motor. Then, the autonomic nervous system is divided one more time into the Sympathetic nervous system – this is your ‘fight or flight’ and the Parasympathetic nervous system or “rest and digest”.

Just a quick recap – the basic parts of the nervous system are the brain, spinal cord, ganglion, and nerves, plus the meninges and cerebrospinal fluid for protection. Each cell is specialized and has a unique function – they all have to be working properly to have proper neurologic function. And the basic divisions of the nervous system are the Central and Peripheral, with the peripheral further divided into somatic and autonomic, which is your sympathetic and parasympathetic nervous systems.

I felt this was super appropriate for nursing students, right? I don’t have a nervous system, I AM a nervous system! Well that is our #1 goal here at NRSNG is to give you peace of mind and make you not feel like such a nervous system!

Make sure you check out the resources within this module and the rest of the neuro course to learn more! Go out and be your best self today! Happy nursing!