In this tissue, the cells and fibres are loosely arranged in a semifluid ground substances, e.g., fibroblasts, macrophages, fat cells and mast cells. Areolar connective tissue present beneath the skin acts as a support framework for epithelium. It acts as a reservoir of water and salts for the surrounding body tissues. Hence, these are called tissue fluid.
Adipose tissue is similar to areolar tissue in structure and function. It is located beneath the skin, surrounding the kidneys, eyeball, heart etc. Adipocytes store fat. It is called white fat. The adipose tissue which contains a lot of mitochondria is called brown fat or brown adipose tissue. Reticular connective tissue is filled with fibroblasts called reticular cells. These cells store fats and the excess nutrients.