it is white to yellowish white in colour
They are large cells, sometimes 100 µm or more in diameter, contain unilocular fat and few poorly developed mitochondria
White adipocytes are spherical, but they may appear polyhedral or oval when crowded together. In contain Unilocular fat droplet with washout during histological preparation. In contain thin rim of cytoplasm & spherical, flatten nucleus. Shape of cell: signet ring shape
Thin cytoplasmic rim of white adipocyte contain a Golgi complex, few poorly developed mitochondria, poorly developed cisternae of the rough endoplasmic reticulum, & free polyribosomes, numerous pinocytotic vesicles & the lipid droplet contains cisternae of smooth endoplasmic reticulum
White adipocyte is predominantly found in adult
Distribution : In subcutaneous tissue, breast, greater omentum, mesenteries, visceral pericardium, orbital cavity , retroperitoneal space, bone marrow
it contains less capillary because it consume less oxygen
It is developed from mesenchymal stem cell which is converted into adipoblast then pre adipocyte and committed pre adipocyte and ultimately form white adipocyte .
The uncoupling protein (UCP) genes belong to the superfamily of electron transport carriers of the mitochondrial inner membrane are not express in white adipocyte
Lipolysis & thermogenesis is regulated by sympathetic innervation in both white & brown adipocytes respectively.
White adipocyte contains less unmyelinated sympathetic nerve. In white adipocytes, sympathetic innervation regulates a cascade of lipolysis to convert stored triglycerides (TG) to free fatty acids (FFA) & glycerol that can be used as fuels of other tissues.
White adipocyte make up about 15-20% of the body mass in men of normal weight, it represents 20-25% of body mass in women of normal weight
Response to environmental stress (cold exposure) :
Increased lipoprotein lipase activity
Growth and differentiation
Throughout entire life from stromal-vascular cells
Functions of White adipocyte: it acts as
metabolic energy storage,
cushioning of vital organs,
secretion of hormones,
source of metabolic water.