Connective Tissue: Connective tissue is the most abundant and widely distributed tissue type found in the human body. The role of connective tissue is to protect, support, and bind together parts of the body. When considering the characteristics that make a tissue a connective tissue, we should consider the following: Connective tissues tend to be very vascular (have a rich blood supply). Some exceptions, such as tendons, ligaments, and cartilages, are less vascularized, but overall, connective tissues possess a great blood supply than the epithelial tissue previously discussed. Connective tissues are made up of many types of specialized cells. Connective tissues contain a large amount of non-living material referred to as the matrix (composed of ground substance and fibers). Typically, this material is manufactured and secreted by the cells of the specific connective tissues. There are four types of connective tissues found in the human body : 1. Connective tissue proper a. Loose Connective Tissue i. Areolar ii. Adipose iii. Reticular b. Dense Connective Tissue i. Dense irregular ii. Dense regular : 1.Fibrous 2.Elastic 2. Cartilage a. Hyaline b. Elastic c. Fibrocartilage 3. Bone (osseous tissue) 4. Blood a.Loose Connective Tissue :this tissue is characterized by loosly arranged fibers and abundance of cells . i.Areolar : Gel-like matrix with all three fiber types; cells: fibroblasts, macrophages, mast cells, and some white blood cells. Location: Widely distributed under epithelia of body, e.g., forms lamina propria of mucous membranes; packages organs; surrounds capillaries. ii. Adipose : Matrix as in areolar, but very sparse; closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet. Location: Under skin in the hypodermis; around kidneys and eyeballs; within abdomen. iii. Reticular : Network of reticular fibers in a typical loose ground substance; reticular cells lie on the network. Location: Lymphoid organs (lymph nodes, bone marrow, and spleen). b. Dense Connective Tissue i. Dense irregular :it characterized by an abundance of fibers and few cells , Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast. (ex.the dermis in skin, Fibrous capsules of organs and of joints). ii. Dense regular :is characterized by ordered and densely packed in parallel arrays of fibers ,includes: 1.Fibrous : Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast. Location: Tendons, most ligaments. 2.Elastic: containing a high proportion of elastic fibers. Location: Walls of large arteries ; within certain ligaments associated with the vertebral column; within the walls of the bronchial tubes.