Major Components of Nerve Tissue

00:02 So let us first of all look at what the major components of nerve tissue is? On this slide, you can see two images. Both these images contain the two major components of nerve tissue. One is the neuron or the nerve fibre. It's often called a nerve fibre because the axonal processes we'll see later on are very very long. So when I use the term neuron or nerve fibre or in fact nerve cell, I'm referring to the same structure. As well as having neurons, throughout the nervous tissue, there are supporting cells called glial cells. And there are a number of different sorts of glial cells and I will describe these sorts of cells both in this lecture and in the next lecture. I want you to look at the right hand side picture, the one showing the glial cell and I want you to try and remember this picture because I am going to ask you to hold it in your memory because I am going to refer back to this glial cell in the next lecture when we talk about glial cells in the brain. Have a very careful look at this image and notice that this glial cell has some very very fine little black fibres or processes moving through the neural tissue. This elongated structure is a bit hard to see because of the stain used, is the blood capillary. And blood capillaries are lined by very thin squamous cells because it is the best sort of design of an epithelial surface or the lining of blood capillary to allow very effective transport of nutrients such as glucose and oxygen into the neural tissue. Now when I describe certain epithelia, I have said that squamous cells particularly those lining blood capillaries in the brain are very tightly bound together. They prevent lots of materials particularly pathogens and even drugs from entering into the nerve tissue. And it is not just because of the structural integrity of the endothelial cell, the squamous cell lining the blood capillary, but it is also due to other components that help that capillary to be very very impermeable and one of those components is this glial cell. But I want you to remember and recall in my next lecture.