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## Neurons and Neuroglia - Neurons are the excitable, impulse-conducting cells that perform the work of the nervous system - Neuroglia protect the neurons ### Neuroglia Also called glial cells, neuroglia are the supportive cells of the nervous system. Glia means "Glue". #### Cell Types ##### Neu...

## Neurons and Neuroglia - Neurons are the excitable, impulse-conducting cells that perform the work of the nervous system - Neuroglia protect the neurons ### Neuroglia Also called glial cells, neuroglia are the supportive cells of the nervous system. Glia means "Glue". #### Cell Types ##### Neuroglia of CNS - Oligodendrocytes form myelin sheaths in the brain and spinal cord, speeding signal conduction ##### Neuroglia of PNS - Schwann cells form myelin sheaths around nerves in the PNS, forming neurilemma #### Blood-brain Barrier Feet of the astrocytes join with the endothelial cells lining the walls of capillaries to create a semi-permeable membrane. The BBB exists throughout the brain and allows small molecules to diffuse across the brain, but blocks larger molecules. This helps protect the brain from foreign substances. It also prevents most medications from reaching brain tissue, making treating brain disorders challenging. #### Life lesson: Gliomas Gliomas are highly malignant and grow rapidly. Because of the BBB, the only treatment options are surgery and radiation. ## Neurons Nerve cells are called neurons. They handle the nervous system's role of communication. ### Three classes of Neurons - **Sensory neurons** (afferent) detect stimuli such as touch, pressure, heat, cold, or chemicals and then transmit information about the stimuli to the CNS.