Adipose Tissue

About the Adipose Tissue

Adipose tissue, or body fat, is a connective tissue made up mainly of fat cells, called adipocytes, along with blood vessels, nerves, immune cells, and precursor cells. White adipose tissue, the most abundant type, stores energy as triglycerides in a single large droplet within each cell, and releases fatty acids when energy is needed. It also cushions organs and provides insulation. Subcutaneous fat lies beneath the skin, while visceral fat surrounds the internal organs in the abdomen; excess visceral fat is more strongly associated with insulin resistance, type 2 diabetes, and cardiovascular disease. Adipose tissue is now recognized as an endocrine organ that releases hormones such as leptin, which signals energy stores to the brain and regulates appetite, and adiponectin, which affects insulin sensitivity. Brown adipose tissue, rich in mitochondria and the protein UCP1, generates heat rather than storing energy, and is prominent in newborns; adults have smaller amounts, mainly in the neck and upper back.