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# Nervous System Components ## Introduction The nervous system is the master integrating and coordinating system. It constantly monitors and processes sensory information from both the external environment and within the body. This system functions like a computer, processing information to prod...

# Nervous System Components ## Introduction The nervous system is the master integrating and coordinating system. It constantly monitors and processes sensory information from both the external environment and within the body. This system functions like a computer, processing information to produce a response. The nervous system comprises two primary divisions: * **Central Nervous System (CNS):** Consisting of the brain and spinal cord. * **Peripheral Nervous System (PNS):** Comprising all nervous elements located outside the CNS; includes nerves, sensory receptors, and clusters of neuron cell bodies. Despite its complexity, nervous tissue is composed of two main cell types: neurons and neuroglia. ## Neuroglia Neuroglia, or glial cells, support and protect neurons within the CNS. Specific types include: * Astrocytes * Oligodendrocytes * Microglial cells * Ependymal cells In the PNS: * Schwann cells (also called neurolemmocytes) * Satellite cells Neuroglia perform various functions: * **Support and protection:** Maintaining the delicate neuron environment. * **Phagocytosis (microglial cells):** Engulf and remove cellular debris. * **Myelination (oligodendrocytes and Schwann cells):** Insulating the cytoplasmic extensions of neurons. * **Capillary-neuron exchanges and chemical environment control:** Maintaining the chemical environment around neurons (astrocytes). *Important Note*: Neuroglia are not capable of generating and transmitting nerve impulses. ## Neurons Neurons, or nerve cells, are the basic functional units of the nervous system. They transmit messages throughout the body in the form of nerve impulses. Although structurally diverse, neurons share common features: * They have a cell body that acts as the biosynthetic center and receptive region. * Slender processes (axons and dendrites) that extend from the cell body. * Clusters of neuron cell bodies are called nuclei in the CNS and ganglia in the PNS. **Neuron Cell Body Structure:** The neuron cell body contains: * A large round nucleus, surrounded by cytoplasm. * **Neurofibrils (cytoskeletal elements):** Providing structural support and transporting substances throughout the neuron. * **Chromatophilic substance:** Darkly staining clusters of rough endoplasmic reticulum involved in protein synthesis.