What process allows the skin to interact with topical chemicals?

The process that allows the skin to interact with topical chemicals is absorption. The skin, particularly the outermost layer known as the stratum corneum, acts as a barrier but is also designed to facilitate the uptake of certain substances. When topical chemicals are applied to the skin, absorption refers to their penetration into the skin layers and their entry into the systemic circulation or into the deeper layers of the skin for various physiological effects.

In absorption, the skin can take in moisture, nutrients, and other active ingredients from products applied externally. Factors such as the chemical composition of the topical agent, its molecular size, and the presence of carriers or enhancers will influence how well and quickly a substance can be absorbed.

Other processes like excretion, filtration, and secretion serve different functions in skin physiology. Excretion refers to the removal of waste products from the body through sweat and sebaceous glands. Filtration typically relates to the process of separating substances, often in reference to fluids or proteins but is not a primary function related to topical chemical interaction. Secretion involves the production and release of substances like sebum and sweat but does not pertain to the uptake of chemicals. Thus, absorption is the most relevant process when discussing how the skin interacts with topical chemicals.