There are several types of passive transport mechanisms that are significant in toxicology:
Diffusion: This is the simplest form of passive transport where small, non-polar molecules such as oxygen and carbon dioxide move freely across the lipid bilayer of cell membranes. Simple diffusion is crucial for the movement of lipophilic toxins.
Facilitated Diffusion: In this process, substances move across the cell membrane with the help of transport proteins. This is essential for the movement of polar and charged molecules that cannot diffuse freely through the lipid bilayer.
Osmosis: This is the diffusion of water molecules through a selectively permeable membrane. Osmosis can affect the distribution of water-soluble toxins within the body.
