Page 275 - 20dynamics of cancer

260 CHAPTER 12

6 out of 16 cells
in the crypt ring
Cell
position

7
4
6
4
5 P
3 sc
4 P

2
3 sc P

2
2 sc P
S
1

P P P

P Paneth cell
1p, 2p Paneth lineage cells
S Stem cell
1 sc 1st transit lineage CSC
2 sc 2nd transit lineage CSC

Figure 12.7 Three-dimensional schematic of a crypt in the mouse small in-
testine. The positions of the individual cells show how things might look in a
typical crypt. The Paneth cells tend toward the bottom, where they contribute
to innate immunity by responding to bacterial infection (Ayabe et al. 2000).
The numbers on the cells show the transit cell generation i, as in the T i of Fig-
ure 12.6. The stem cells vary in actual cellular position in the range 3–7, but on
average appear to be around cell position 4 when numbered from the bottom.
The figure only shows the bottom 7 cell positions of the approximately 15 posi-
tions. CSC abbreviates “clonogenic stem cell” (see Figure 12.6). Redrawn from
Marshman et al. (2002).