This essay will look at different types of human tissues and will describe brief characteristics of four main types of tissue (figure 1.1). Furthermore it will investigate two different types of tissues 1 and 2 from the diagrams in more depth and will look at where each tissue is found in the body. Also it will discuss their roles and relate the structure of each tissue to its function.
McGuiness (2002) defines tissue as a group of cells that act together to perform a specific function. However, Hall (2005) state that tissue is a group of similar cells that form the main fabric of human body. From this can be noted that some tissues are soft, like the inner layers of the skin, others are hard, such as bone and fingernails.
Different tissues combine to form more complex structures called organs. An organ usually has a specific function in the organism, for example, to detect light, to absorb food or to produce a hormone (Boyle and Senior, 2008). There are four basic or primary types of tissues (Figure 1.1). These are epithelial tissue, muscle tissue, connective tissue and nervous tissue (Layman 2003). All four types of tissue have special purposes, and therefore have varying different rates of cellular regeneration .For example bone tissue and adipose connective tissue are highly vascular and therefore heal quickly, unlike cartilage tissue is almost the slowest to heal (McGuiness, 2002).
By basic or primary, it is meant that all of the specific types of tissues found in living things (especially humans and animals) are modification or specialisation of these four types of tissues (Layman, 2003).
Epithelial tissue is a covering and lining tissue. It covers body surfaces in general, and lines cavities within the body interior (Layman, 2003). Epithelial tissue, for example, forms the outermost layer of the human skin. According to Layman (2003), epithelial tissue is almost entirely cellular in nature, with little or no intercellular material between its cells (figure 1.1 A).