Why there is no typical cells
Typical here means representative of the whole.  

from the google dictionary


  typ·i·cal ˈtipik(ə)l/Submit adjective having the distinctive qualities
  of a particular type of person or thing. "a typical day"
  synonyms: representative, classic, quintessential, archetypal, model,
  prototypical, stereotypical, paradigmatic;


There is such a variety of cells in the body no one is really typical.  Like a typical human.  Who would that be?  Me?  Chinese lady?  Indian kid?  There are many of us and a lot of variety.  Maybe you could say "typical older Scotsman" or "typical arrogant Stack Question answerer".  You could definitely say "typical liver cell"; narrowing down the zone limits the variety possible and lets you more accurately characterize a call as prototypical or representative.