34) Connective Tissue

Connective tissue is the most abundant and widely disturbed tissue of the body. Its functions include support, protection, binding, insulation and transportation (blood). Connective tissues originate from embryonic mesenchyme and exhibit matrix. Depending on the type, a connective tissue may be well vascularized (most connective tissue), poorly vascularized (dense connective tissue) or avascular (cartilage).
Connective Tissue Types:
1) Embryonic Connective Tissue: a gel-like ground substance containing fibers and star-shaped mesenchymal cells. Is embryonic connective tissue (hence the name). Gives rise to all other connective tissue types. Located primarily in the embryo.
2) Connective Tissue Proper: loose connective tissue, areolar: gel-like matrix with all three fiber types. Contains fibroblasts, macrophages, mast cells and also some white blood cells. It is a soft packing tissue in the body. Warps and cushions organs and has macrophages phagocytize bacteria. It plays an important role in inflammation and holds and conveys tissue fluid. Widely distributed under epithelia of the body, forms lamina propria of mucous membranes, packages organs and surrounds capillaries.
3) Connective Tissue Proper: loose connective tissue, adipocytes: has a matrix as in areolar but very sparse. has closely packed adipocytes (fat cells). Has the nucleus pushed to the side by a large fat droplet. Provides reserve food fuel, insulates against heat loss and supports and protects organs. Located under the skin; around kidneys, eyeballs, within abdomen and breasts.
4) Connective Tissue Proper: loose connective tissue, reticular: a network of reticular fibers in a typical loose ground substance. The reticular cells lie on the network. The fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells and macrophages. Located in the lymphoid organs (lymph nodes, bone marrow and spleen).
5) Connective Tissue Proper: dense connective tissue, dense regular: primarily parallel collagen fibers and a few elastin fibers. Has fibroblast cells. Attaches muscles to bones or muscles to muscles or bones to bones. Withstands great tensile stress when pulling force is applied in one direction. Located in tendons, most ligaments and aponeroses.
6) Connective Tissue Proper: dense connective tissue, dense irregular: primarily irregular arranged collagen fibers with some elastic fibers. Also contains fibroblast cells. Able to withstand tension exerted in many directions and provides structural strength. Located in the dermis of the skin, the submucosa of the digestive tract and the fibrous capsules of organs and of joints.