Histology is the study of tissues. Tissues are groups of cells that are similar in structure and function. There are four tissue types associated with animals such as humans. They are:

epithelial_tissue,

connective_tissue (CT),

muscle_tissue, and

nerve_tissue

Each of these tissue categories has distinctive cell shapes and functions.

Connective tissue is the most abundant and variable of the human tissues. It is designed for supporting, protecting, and binding the tissues of the body. Most CT's are well vascularized (except for tendons, ligaments, and cartilage). Connective tissues all consist of three elements: (1) CT cells, (2) matrix produced by the CT cells, and (3) fibers produced by the CT cells. There are many types of cells associated with CT, but the generic "CT precursor" is the fibroblast.

Matrix is produced by the CT cells, then released from the cells. It is noncellular and nonliving. It provides extracellular support for the CT cells that produced it. There are several types of fibers in CT. The three major types are collagen, elastic, and reticular.

NOTE:

(1) There are three types of cartilage: (1) hyaline, (2) elastic, and (3) fibrous_cartilage.

(2) Fibrocartilage has a matrix so filled with collagen fibers that the chondrocytes and their lacunae are barely visible.