a) Spleen

SPLENIC CIRCULATION.
The spleen is like the maze into which the Cretan king Minos sent his prisoners.
Inside the maze was a vicious creature (half-man, half-bull) who would kill the
trapped prisoners. As far as the trapped red blood cell is concerned, the
macrophage is like the Minotaur (and that's no bull!).
SOURCE: Dr. Jim Faix