Fat globule

In human cell biology globules of fat are the individual pieces of intracellular fat inside cell types other than adipocytes (fat cells). Intracellular fat is bound in the globular form by phospholipid membranes, which are hydrophobic. This means that fat globules are insoluble in water.

In simpler terms: a vacuole or droplet of triglyceride or some other blood lipid, which is located inside a cell that is not an adipocyte (fat cell), as opposed to fat cells in between other cells in an organ. Lipids and any lipid digestive derivatives must be transported in the globular form within the cell, blood and tissue spaces due to its insolubility.

Globules of fat are emulsified in the duodenum into small droplets by bile salts during food digestion, speeding up the rate of digestion by the enzyme lipase at a later point in digestion. Bile salts possess detergent properties that allow them to emulsify fat globules into smaller emulsion droplets, and then into even smaller micelles. This increases the surface area for lipid-hydrolyzing enzymes to act on the fats.^[1]

Micelles are roughly 200 times smaller than fat emulsion droplets, allowing them to facilitate transport of monoglycerides and fatty acids across the surface of the enterocyte, where absorption occurs.^[2]

Milk fat is another form of intracellular fat found in the mammary glands of female mammals. In this form, fat globules or droplets are formed through the synthesis of phosphatidylcholine^[3] to regulate globule formation.

See also

• Steatosis

References