There are two types of adipose tissue, white adipose tissue (WAT) and brown adipose tissue (BAT), which are also known as white fat and brown fat, respectively, and comprise two types of fat cells:
- White fat cells (also known as Unilocular Cells) contain a large lipid droplet surrounded by a ring of cytoplasm. The nucleus is flattened and located on the periphery.
- Brown fat cells (also known as Multilocular Cells) are polygonal in shape. Unlike white fat cells, these cells have considerable cytoplasm, with lipid droplets scattered throughout. The nucleus is round, and, although eccentrically located, it is not in the periphery of the cell. The brown color comes from the large quantity of mitochondria. Brown fat, also known as "baby fat," is used to generate heat.
Areolar connective tissue is composed of adipocytes.
- Histology image: 08201loa – Histology Learning System at Boston University - "Connective Tissue: unilocular (white) adipocytes "
- Histology image: 04901lob – Histology Learning System at Boston University - "Connective Tissue: multilocular (brown) adipocytes"