NSC - Tissues of the Nervous System Lesson

AandP_Lesson_TopBanner.png 

Tissues of the Nervous System

Nervous tissue is primarily made of two types of cells: neurons and neuroglia.

A diagram of a nervous system tissue cell.

Neurons

Neurons are the basic functional unit of the nervous system specialized in carrying "messages" throughout the body. Like other cells, neurons are surrounded by cell membranes, have nuclei that contain genes, contain organelles, and carry out basic cellular processes such as protein synthesis and energy production. However, neurons also contain specialized structures that allow them to communicate through an electrochemical process.  

To review the anatomy of a basic neuron, roll your cursor over the name of each part below to see a description:

Neurons are some of the oldest cells in your body since you keep many of the same neurons for your entire life. Unlike other cells, when neurons die they are typically not replaced. Neurons are also some of the longest cells of your body, with some axons stretching over several feet. Remember that not all neurons look alike. Their structure will largely depend upon their functional need. Here are some examples of different types of neurons below:

There are four types of neurons: Unipolar, bipolar, multipolar, and pseudo-unipolar.

Another way to classify neurons is by the direction that they send information.

Sensory (Afferent) Neuron

Motor (Efferent) Neuron

Interneuron

Information is sent from sensory receptors to the CNS. Information is sent from the CNS to muscles or glands. Relays information between sensory and motor neurons. 

 

Watch the video below to learn how scientists are studying the structures of neurons to develop artificial intelligence in robots:

When looking at nervous tissue, some regions are composed mainly of cell bodies whereas others are composed of mainly axons. These two regions are often referred to as gray matter and white matter, respectively. Gray matter is not always gray (it can be tan, or even pink, depending upon blood content) but white matter does typically appear white because of the "fatty" myelin sheath covering the axons. The difference between these two tissues is most distinctive in the central nervous system.

A human brain with gray matter and white matter.

 

 

Neuroglia (Glial Cells)

An illustration of a glial cell.

Neuroglia or glial cells is the general name for a type of support cell in the nervous system that maintains homeostasis, forms myelin, and provides support and protection for neurons in both the CNS and PNS.  

There are four main functions of glial cells:

          1. To surround neurons and hold them in place
          2. To supply nutrients and oxygen to neurons
          3. To insulate one neuron from another
          4. To destroy pathogens and remove dead neurons.

 

 

 

Roll your cursor over the image of each of the glial cells below to learn about its specific function.

Use the interactive activity below to review the content of this module:

AandP_BottomBanner.png 

IMAGES CREATED BY GAVS OR OPENSOURCE