Streaming intestinal lining

This presentation summarizes the current knowledge on the kinetics of G. I. tract epithelia
.
Properties of G. I. tract epithelia

1. Their unit is called  :Epithelial Proliferative Unit  (EPU)
2. EPU is monoclonal
3. EPU is oriented from stem cell and outward
4. Cells stream outward (to their graveyard)
5. As cells stream they differentiate.
6. Cells do not stream inward, they do not de-differentiate.

Time dimension of histopatology
Cells are born during a stem cell  division, and stream away toward
their graveyard. Their distance from  the stem cell is their biological age.

More on streaming tissues:
http://www.what-is-cancer.com/papers/contents/streamingFrame.htm