Making the world better, one answer at a time. Endothelial and epethelilal cells are the two different cell types which sandwich together the tissue. On the blood side is the endothelial cells (endo, meaning inside), and on the outer side are the epethelial cells.or example the epethelial cell layer are the cells that coat the intetestine wall, and thus absorb nutrients and the the endothelial cells are the cells that face the blood,and release those nutrients into the blood.