The next type of tissue is the connective tissue. Connective tissue is composed of cells that produce different types of protein fibers that are exuded from cells that develop a matrix of protein and fluids that connect different tissues of the body into a network of tissues that provides functional units of the organ systems of the body. There is a vast array of connective tissue structures and functions throughout the body, figure 12. Each type of connective tissue has different cells that provide the materials for the matrix and the matrix of the connective tissue will differ to match the desired function of the connective tissue type.
<<INSERT FIGURE 12 ABOUT HERE>>
We generally use three distinct classes of tissues to describe the array of cells and tissues that comprise the connective tissues. There is true connective tissue, which forms a protein matrix that connects tissues to each other that are classified as being either dense or loose, figure 13. There is support: forms solid matrices that form the rigid or semi-rigid structures of the body, figure 14. Then there is the liquid: protein matrix is dissolved within an aqueous solution, used for transportation connection between tissues and includes tissues such as blood and lymph.
<<INSERT FIGURE 13a ABOUT HERE>>
<<INSERT FIGURE 13b ABOUT HERE>>
There are distinct classifications of cells for the connective tissue. These cells are determined and identified either by the type of tissue (i.e. chondrocyte for cartilage), or by distinct cellular identifier (i.e. erythrocyte or leukocyte for blood cells based on carrying of hemoglobin molecule), or if happens to be protein fiber producing cell (i.e. fibrocytes within the connective tissue matrix). Additionally we will classify cells based on two distinct behaviors that the cells have toward the maintenance of the connective tissue matrix. The blastic cells (blasts) are responsible for developing and building the matrix of the connective tissue. The clastic cells (clasts): are responsible for degrading and recycling of the materials that comprise the matrix. Lastly, cells can be identified by where they are located, being either fixed (stationary within the matrix) or wandering (able to move within the matrix).
<<INSERT FIGURE 14 ABOUT HERE>>
Each and every type of connective tissue will have a distinct type of matrix and different types of cells with the matrix. “True” connective tissues will be fibrocytes, cells that generate and recycle protein fibers. “Structure” connective tissue will be composed of chondrocytes, cells that generate and recycle cartilage, and Osteocytes, cells that generate and recycle bone. “Fluid” connective tissue will consist of the erythrocytes, lymphocytes and macrophages. Within the connective tissues the cells will exude a variety of protein fibers, the most abundant of these fibers are collagen and elastin proteins, with a third type of fiber known as reticular fibers.