D. Connective tissues 1. General features a. Most abundant tissue in the body b. Has three basic elements: cells, ground substances, and fibers c. Do not occur on free surfaces d. All but cartilage has nerves and is highly vascularized e. Matrix is secreted by cells and determines qualities

2. Cells of connective tissues a. All are derived from the mesenchyme 1. Immature cells end in –blast, mature cells end in –cyte b. Fibroblasts, which secrete fibers and matrix, macrophages (wbc), mast cells, adipocytes and plasma cells are common in all connective tissues

3. Ground tissues of connective tissues a. it contains hyaluronic acid, chondraton sulfate, dermatin sulfate, and keritin sulfate b. Supports, binds, provides exchange medium, and influences cell function

4. Connective tissue fibers a. 3 types of fibers provide strength and support 1. Collagen fibers are tough and resistant to stretching but allow some flexibility 2. Elastic fibers of elastin provide strength and stretching capacity 3. Reticular fibers of collagen and glycoprotein are a support and framework structure

5. Embryonic tissue a. Embryonic connective tissue is primarily in an embryos or a fetus b. Mesenchyme, the primary and exclusive tissue of an embryo, is the source of all connective tissue c. Mucous connective tissue is found in the umbilical cord for support 1. AKA Wharton’s Jelly