1. Neurons:
* Function: Neurons are the basic functional unit of the nervous system. They are responsible for receiving, processing, and transmitting information throughout the body. This information can be in the form of sensory input, motor commands, or internal body signals.
* Structure: Neurons have a unique structure that allows them to perform their function effectively. They consist of:
* Cell body (soma): Contains the nucleus and other organelles essential for the neuron's survival and function.
* Dendrites: Branching extensions that receive signals from other neurons or sensory receptors.
* Axon: A long, slender projection that transmits signals to other neurons, muscles, or glands. The axon is often covered in a myelin sheath, which insulates the axon and speeds up signal transmission.
2. Glial Cells (Neuroglia):
* Function: Glial cells are non-neuronal cells that provide support and protection for neurons. They are essential for the proper functioning of the nervous system and perform a variety of functions, including:
* Structural support: Glial cells help to hold neurons in place and provide a framework for the nervous tissue.
* Myelination: Some glial cells produce myelin, a fatty substance that insulates axons and speeds up signal transmission.
* Nutrient supply: Glial cells help to transport nutrients and oxygen to neurons.
* Waste removal: Glial cells remove waste products from the nervous tissue.
* Defense: Glial cells can help to protect the nervous system from infection and injury.
Types of Glial Cells:
* Astrocytes: Star-shaped cells that provide structural support, regulate the chemical environment of neurons, and help to maintain the blood-brain barrier.
* Oligodendrocytes (in the CNS) / Schwann cells (in the PNS): These cells produce myelin sheaths that insulate axons.
* Microglia: These cells are the immune cells of the nervous system, engulfing debris and pathogens.
* Ependymal cells: These cells line the ventricles of the brain and the central canal of the spinal cord, producing cerebrospinal fluid.
Together, neurons and glial cells create the complex and intricate network of nervous tissue that enables us to think, feel, move, and interact with the world around us.
