Final answer:
The skin is permeable to organic solvents because they can dissolve the lipid bilayers of cell plasma membranes, allowing these non-polar or lipid-soluble substances to easily pass through the skin's amphiphilic plasma membranes and enter the bloodstream.
Step-by-step explanation:
The skin is permeable to organic solvents, such as acetone or turpentine, because they can dissolve the lipid bilayers of epidermal and dermal cell plasma membranes.
Organic solvents are generally non-polar or lipid-soluble substances, which easily diffuse through the amphiphilic plasma membranes of cells. The plasma membrane has a hydrophobic (lipid) interior that allows these kinds of molecules to pass through. This is because the solvents can disturb the highly ordered structure of lipid molecules, leading to increased permeability of the skin layers. Hence, solvent molecules like acetone can penetrate the skin quickly and enter the bloodstream. Once they pass the epidermal layer, they reach the capillaries in the dermis, from where they can be transported to other parts of the body. It's important to note that while this property can be useful for administering certain medications transdermally, it also represents a potential route of exposure to toxic substances.
These solvents have the ability to pass through the hydrophobic core of the plasma membrane, which is primarily composed of lipid molecules. As a result, they can easily enter the bloodstream and affect various physiological processes in the body.