What is Nervous Tissue?
Nervous tissue has two main functions: sensing stimuli and sending impulses to different parts of the body as a response. Nervous tissue is what makes up the body’s nervous system, which is split into the central nervous system and the peripheral nervous system. Central nervous tissue can be found in the brain and spinal chord. The peripheral nervous system is made up of all nervous tissue outside of these areas. Peripheral nervous tissue gathers signals from all parts of the body and sends them to the central nervous system. Nervous tissue is responsible for many of the body’s activities and processes, including memory, reasoning and emotions. Signals from nervous tissue also cause muscle contractions.
Nervous tissue is formed by neurons and glial cells. Humans have billions of neurons, which vary in size, in their bodies. Neurons can be broken down into the cell body, which contains each neuron’s nucleus and mitochondria, and nerve processes. Nerve processes are made of cytoplasm and resemble thin fingers. They extend outward from the neuron and are responsible for transmitting signals both to the neuron and away from it. There are two types of nerve processes: axons and dendrites. Axons carry messages away from the neuron and dendrites transmit signals to the neuron. Axons and dendrites come together to form nerves.
Glial cells, called neuroglia when located in the central nervous tissue, are often found in bunches around neurons in both the central and peripheral nervous systems. These nervous tissue cells are smaller than neurons. Glial cells have a special function when surrounding axons, though they do not transmit neurological signals. These glial cells, called Schwann cells, provide the neurons of the nervous tissue with support, nutrition, and protecting neurons against bacteria. They hold the neurons together. Other types of glial cells include microglia and oligodendrocytes. Microglia help repair damage to the neurons. Oligodendrocytes support the axons.
Written by Jennifer Fenn
