By BruceBlaus. When using this image in external sources it can be cited as: Blausen.com staff (2014). "Medical gallery of Blausen Medical 2014". WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. - Own work, CC BY 3.0, Link
By LadyofHats Mariana Ruiz Villarreal - Own work. Image renamed from Image:Simple_difussion_in_cell_membrane.svg, Public Domain, Link
By LadyofHats Mariana Ruiz - did it myself, Public Domain, Link
By LadyofHats - did it myself based on [1], [2] ,[3] and [4]., Public Domain, Link