What are nerve tissues composed of? What are the functions of these tissues?

Nerve tissues are primarily composed of two types of cells: neurons and neuroglial cells (or simply glial cells).

Neurons are the basic structural and functional units of the nervous system. They are specialized cells that transmit electrical signals, called nerve impulses, throughout the body. Neurons have three main parts: the cell body (also known as the soma), dendrites, and an axon. The cell body contains the nucleus and other organelles necessary for the cell's function. Dendrites are branched extensions of the cell body that receive incoming signals from other neurons and transmit them towards the cell body. The axon is a long extension that conducts nerve impulses away from the cell body towards other neurons, muscles, or glands.

Neuroglial cells, also known as glial cells, are supporting cells in the nerve tissue. They significantly outnumber neurons and play a crucial role in maintaining the proper function of the nervous system. There are different types of glial cells, including astrocytes, oligodendrocytes, microglia, and Schwann cells. Each type has specific functions: 1. Astrocytes: They provide physical and nutritional support to the neurons, maintain the blood-brain barrier, regulate the environment around the neurons, and help form synapses, the junctions between neurons. 2. Oligodendrocytes: They produce myelin, a fatty substance that insulates axons and allows for faster conduction of nerve impulses within the central nervous system. 3. Microglia: They are the immune cells of the nervous system, responsible for defending the nervous tissue against pathogens, removing cellular debris, and performing other clean-up tasks. 4. Schwann cells: Like oligodendrocytes, Schwann cells produce myelin, but they do so in the peripheral nervous system.

The main functions of nerve tissues are to transmit electrical signals or nerve impulses throughout the body, allowing for communication and coordination between different body parts and organs. Nerve tissues enable organisms to react and respond to their environment, process sensory information, and generate thoughts and emotions. Additionally, glial cells play a crucial role in maintaining the health and proper functioning of neurons. They provide structural support, insulate axons, protect from injury, and maintain the extracellular environment.