Table of Contents
Tissues refer to a collection of similar cells which are organized to perform particular functions (Sherwood, 2009). Tissues can be of various types. There are four different types of tissue cells these are; muscular, connective, neural and epithelial tissues (Martin & Nath, 2009).
The epithelial tissues are found on the body surface and cover both the internal and external body parts (Martin & Nath, 2009). The cells of the epithelial cells replicate through mitosis. These cells are specialized in order to allow for exchange of materials between the environment and cells. The epithelial cells are further divided into the secretory glands and the epithelial sheets. The epithelial tissue is found lining various parts of the body such as the skin and the lining of the digestive tract (Martin & Nath, 2009).
The muscle tissue is specialized for contraction. The muscle tissues are necessary for body movement. The muscle tissues are of three main types these are;
Skeletal muscle tissue
The skeletal muscle is striated and is attached to the bones. These muscles help to support and move the skeleton (Martin & Nath, 2009). The skeletal muscles usually have multiple nuclei which are usually located peripherally. These muscles contract only after they are stimulated by the nerves (Martin & Nath, 2009). When these muscles contract, they move the bone which they are attached to in order to produce movement.
Cardiac muscle tissue
This muscle is found in the heart only. The cardiac muscle cells are interconnected in regions known as intercalated disc (Martin & Nath, 2009). These muscles do not require nerve activity in order to contract. The contraction of these muscle cells is governed by the pacemaker cells which are specialized cardiac muscles (Clark, 2005). Cardiac muscles have a limited ability to repair themselves because they are not able to regenerate.
These are found in walls of blood vessel. The smooth muscle cell is spindle shaped and has tapering ends with a single nucleus (Martin & Nath, 2009). This tissue is capable of regenerating its self because the cells can divide even after injury. This muscle tissue is found on the walls of the digestive respiratory, digestive, circulative and reproductive tract (Sherwood, 2009).
The connective tissue
The connective tissues are important because it is necessary for connecting and support. With this kind of role this tissue is found in various parts of the body. The connective tissue provides a means of joining the other tissues (Clark, 2005). The cells of the connective tissues are embedded by a matrix. Interestingly the connective tissue has more matrix than cells. The matrix varies from fluid to gel depending on the type of connective tissues. The loose connective tissue comprises of a loose arrangement of the fibroblasts cells and collagenous fiber (Martin & Nath, 2009). The dense connective tissue is similar in composition to the loose connective tissue. However, the dense connective tissues are stronger because the fiber is densely arranged and abundant. The dense connective tissue is used where strength is needed. Tendons and ligaments are made up of the dense connective tissue. The elastic connective tissue is made up stretchy fibers which allow for elasticity (Martin & Nath, 2009). The fibers in this case are made of elastin the elastic connective tissue is found in the great arteries which must stretch as the heart pumps blood through them (Martin & Nath, 2009).
The neural tissue plays the role of initiating and transmitting nervous impulses from the sensory to the receptive tissue. This tissue is found in the brain, spinal cord and other special sense organs. The neural tissue comprises of the neurons and the neuroglia (Sherwood, 2009). Signals transmitted by the neurons mostly affect the cell membranes. The Neuroglia on the other hand supports the neural tissue and provides protection to the neurons. One notable thing with the neural cells is that they are not able to repair themselves once they are damaged (Martin & Nath, 2009).