What is one of the chemical defenses provided by the skin?

Sebum is a vital component of the skin's chemical defenses, produced by sebaceous glands. It is an oily substance that helps to create a hydrophobic barrier on the skin's surface, which plays a critical role in preventing the entry of pathogens, such as bacteria and fungi. The presence of sebaceous glands and the resulting sebum also assist in keeping the skin moisturized and maintaining its integrity, which is essential for overall skin health and protection against microbial invasion.

In contrast, younger skin cells focus on the renewal and repair of the skin rather than serving as a defense mechanism. Sweating, while important for thermoregulation and helping to rid the body of toxins, does not offer direct chemical protection against pathogens in the way that sebum does. The dermis, being the layer of skin beneath the epidermis, provides structural support and houses blood vessels and nerves but does not contribute chemically to the skin's defenses against infections. Thus, sebum stands out as an essential chemical defense method provided by the skin.