Adipocyte

Your body has tiny fat cells.

These cells store food for later.

There are two main kinds. White fat cells store energy. Brown fat cells help make heat.

This is often called "baby fat."

These cells can change size. They can also change in number. This happens as children grow up.

Some cells live inside your bones. These are called marrow fat cells.

Fat cells also send signals. One signal helps tell you when you are full.

Your body has many tiny cells called adipocytes.

These are fat cells. They store energy for your body to use later.

There are two main types of fat cells. White fat cells have one large drop of fat inside. This drop pushes the cell's center to the side.

Brown fat cells are different. They have many small fat drops inside. These cells have many mitochondria, which are tiny parts that make power. This gives them a brown color. Brown fat helps make heat.

Fat cells can change as you grow. Children can grow more fat cells. Adults usually just grow larger fat cells. An adult has about 30 billion fat cells. This can weigh about 30 pounds.

Fat cells also act like messengers. They make a hormone called leptin. Leptin is a signal that helps tell your brain when you are full.

Some fat cells also live inside your bones. We call these marrow fat cells.

Adipocytes are special cells that make up adipose tissue. Most people know them as fat cells. Their main job is to store energy for the body to use later.

These cells are very important for how our bodies work. They do more than just hold energy. They also act like messengers by making proteins called adipokines. One important messenger is leptin, which helps tell the brain when you are full.

There are two main types of fat cells in the body. White fat cells are called unilocular because they have one large lipid droplet. This big drop of fat pushes the cell's center to the edge.

Brown fat cells are different and are called multilocular. They have many small fat droplets scattered inside. These cells look brown because they have many mitochondria, which are parts that make power. Brown fat is often called "baby fat" because it helps generate heat.

How these cells grow depends on your age. In children and adolescents, the total number of fat cells can increase. If an adult gains weight, their fat cells usually just get larger. This is called hypertrophy. If the cells grow very large, the body might make more of them. This is called hyperplasia.

An average adult has about 30 billion fat cells. These cells can weigh around 30 pounds or 13.5 kg. About 10% of these cells are replaced every year.

Scientists study how these cells are made from stem cells. These cells start as mesenchymal stem cells. They can turn into many different things like muscle or bone. The early version of a fat cell is called a lipoblast.

These cells also respond to things like insulin. Insulin helps the cells take in glucose and build fat. This process involves special proteins like SREBF1 and SCAP. These proteins work together to manage how the cell stores energy.

Fat cells can be found in different places in the body. Some live in the marrow inside your bones. These are called marrow adipocytes. They are similar to white fat cells.

Research shows that exercise can reduce the size of these marrow fat cells. This is something that can be seen using special medical imaging. Understanding these cells helps us learn how the body manages weight and energy. It also helps us understand how our bodies stay warm and healthy.

Adipocytes are specialized cells that primarily compose adipose tissue. Most people know these cells simply as fat cells. Their main biological purpose is to store energy in the form of fat.

Beyond simple storage, adipocytes are active participants in the body's internal communication. They secrete many different proteins known as adipokines. These include substances like leptin, which helps regulate appetite by signaling satiety to the brain. Other examples include adiponectin, resistin, and apelin. Because they manage energy and hormones, adipocytes are essential to overall metabolic health.

There are two distinct types of fat cells: white and brown. White fat cells are described as unilocular. This means they contain a single, large lipid droplet that occupies most of the cell. This droplet is composed mainly of triglycerides and cholesteryl ester in a semi-liquid state. The large droplet pushes the nucleus to the very edge of the cell.

In contrast, brown fat cells are multilocular. They have a polyhedral shape and contain several smaller lipid droplets scattered throughout the cytoplasm. These cells appear brown because they contain a very high quantity of mitochondria. Often called "baby fat," brown adipose tissue is used by the body to generate heat.

A third type of fat cell is found within the bone marrow. These are called marrow adipocytes. Like white fat cells, they are unilocular in structure. Scientists are still studying their exact physiologic functions and how they relate to bone health. Research shows that marrow adipose tissue expands in cases of obesity or low bone density. However, it also responds to physical activity. Exercise has been shown to reduce both the size of these cells and the total volume of marrow adipose tissue.

Adipocytes develop through a process called adipogenesis. They originate from mesenchymal stem cells. These stem cells are versatile and can differentiate into many different things, such as bone, muscle, or connective tissue. The precursor to an adult fat cell is known as a lipoblast.

If these precursor cells develop into a tumor, it is called a lipoblastoma. The way body fat is distributed during normal growth depends on nutrition and hormones. These factors interact with the intrinsic differences found in various adipose tissue depots.

The way fat cells change depends heavily on a person's age. An average human adult possesses approximately 30 billion fat cells. These cells have a combined weight of about 30 lbs, or 13.5 kg. During childhood and adolescence, the absolute number of fat cells can increase if a person gains excess weight. This increase can continue until age twenty-four. In adults who were not obese as children, weight gain usually causes existing cells to increase in size, a process called hypertrophy. While some evidence suggests the number of cells might increase during severe obesity, this is not always the case. Interestingly, about 10% of fat cells are renewed every year in adults.

Insulin plays a major role in how adipocytes function. It strongly stimulates the production of fat within these cells. To do this, insulin promotes glucose uptake and controls specific enzymes like pyruvate dehydrogenase and acetyl-CoA carboxylase. This process involves a complex molecular chain. A protein called SREBF1 is synthesized as an inactive precursor in the endoplasmic reticulum. It binds with a protein called SCAP. When sterol levels are low, the INSIG1 protein releases this SREBF1-SCAP complex. The complex moves to the Golgi apparatus, where SREBF1 is cleaved into its active form.

This active protein then moves to the nucleus to activate genes for fat storage.

Adipocytes also have significant endocrine roles. They can synthesize estrogens from androgens. This chemical process may be a reason why being underweight or overweight can impact fertility. Furthermore, the way these cells respond to overfeeding can vary by body location. In the upper body, fat gain is mostly linked to an increase in cell size. In the lower body, research has shown that the actual number of fat cells can increase significantly. Understanding these complex mechanisms helps scientists study metabolic diseases and how the body adapts to different nutritional pressures.