After the modeling and sculpting, I painted the textures for the heart and liver. The textures on the lungs, stomach and intestines are just procedural textures that I just made up for this rendering.
Actually in the final animation, only the liver will be visible as a normal shading mode, the other organs will be rendered with transparencies. This project is about the life cycle of Malaria in the human body and in the mosquito. So in this case, with the semi-transparent organs, the camera will be showing the Malaria parasite flowing through the circulatory system into the liver.