What substance is produced by the sebaceous glands?

Sebum is the substance produced by the sebaceous glands, which are located in the skin. This oily secretion plays a crucial role in maintaining the health and integrity of the skin and hair. Sebum helps to keep the skin moist, prevents it from becoming too dry, and provides a barrier against harmful bacteria and fungi. It is composed of a mixture of lipids, including triglycerides, wax esters, squalene, and free fatty acids, all of which contribute to its emollient properties.

The other substances listed are produced by different types of cells or glands. Collagen is a structural protein found in connective tissues, keratin is a protein that forms the structure of hair, nails, and the outer layer of the skin, and melanin is the pigment responsible for skin and hair color, produced by melanocytes. Understanding the function of sebum and its origin is important for comprehending skin health and the role of the sebaceous glands in protecting and nourishing the skin.