So we have four different types of ways in which our cells can organize themselves into these groups known as tissues. We have epithelial tissue, muscle tissue, connective tissue as well as nervous tissue. Now, let's begin by generalizing each one of our tissues. Let's begin with the epithelial tissue. Now, the epithelial tissue consists of individual cells that basically serve to cover the outside portion of the body as well as the internal cavities such as the stomach, the small and large intestine as well as the kidneys. Now, these cells, the epithelial cells of the epithelial tissue are not only involved in protecting our body from outside harmful sources such as bacteria, viruses or UV radiation these cells are also responsible for absorption as well as secretion.