Final answer:
Adipose tissue is a connective tissue made up of adipocytes, which store fat for energy, insulate the body, and protect organs. It is essential for energy metabolism and exists as white and brown types, with the former providing insulation and the latter generating heat during fat metabolism.
Step-by-step explanation:
Adipose tissue is a type of connective tissue that is mainly composed of fat-storage cells known as adipocytes. Despite its sparse extracellular matrix, it is integral to various physiological processes such as energy metabolism, thermal insulation, and organ protection. Fat is stored in adipocytes as triglycerides and, upon need, is broken down into glycerol and free fatty acids for energy. There are two main types of adipose tissue: white adipose tissue, which stores lipids and insulates the body, and brown adipose tissue, which is thermogenic and promotes heat production during fat metabolism.
Adipose tissue also offers mechanical cushioning for the body organs, such as protecting the kidneys and the back of the eye. Furthermore, the large number of capillaries in adipose tissue facilitates the rapid storage and mobilization of lipid molecules. In metabolic terms, the glycerol released during triglyceride breakdown is sent to the liver for further oxidation, while the free fatty acids are re-esterified in the adipose tissue itself.