Diffusion of Chemicals from a Transdermal Patch Must Reach What

Question

Diffusion of chemicals from a transdermal patch must reach what layer of the skin to be effective?
A) dermis
B) hypodermis
C) epidermis

Accepted Answer

The dermis layer of the skin contains blood vessels and nerves that allow for the diffusion of chemicals from a transdermal patch to reach the bloodstream and be effective. The epidermis is the outermost layer of the skin and the hypodermis is the layer of fat tissue below the skin, neither of which would allow for effective diffusion of chemicals from a transdermal patch.