Loose connective tissue, a sub-type of connective tissue proper, is the most abundant type of connective tissue, composed of loosely arranged fibers and a few cells suspended in a dense ground substance. In an embryo, it is present under the skin as mesenchymal tissue and in the umbilical cord as the mucoid connective tissue. Adults have areolar, adipose, and reticular loose connective tissues. Areolar tissues have a loose meshwork of collagen, elastic and reticular fibers combined with interstitial fluid and scattered cells. Areolar tissues connect epithelial cells to the underlying tissue, such as connecting the epidermis to the muscle underneath the skin. These tissues also form a protective covering around the lymphatic and blood vessels. Adipose tissues primarily comprise adipocytes or fat cells, which have lipid droplets for long-term energy storage. These are found below the subcutaneous layer or around organs and act as shock-absorbing cushions. Reticular tissues comprise fine, branched reticular fibers and fibroblasts. These tissues provide a supporting framework in lymphatic organs such as the lymph nodes, spleen, tonsils, and bone marrow.