Connective tissue connects different body parts structurally and functionally. There are four main types of connective tissue: general connective tissue, blood, cartilage, and bone. General connective tissue includes loose connective tissue (areolar and adipose tissue) and dense connective tissue (dense regular and dense irregular). Areolar tissue contains collagen, elastic, and reticular fibers in a matrix and is found under the skin and around blood vessels. Adipose tissue contains lipid-filled adipocytes and acts as insulation under the skin.