Morphogenetic Mechanisms in the Cyclic Regeneration of Hair Follicles and Deer Antlers from Stem Cells

Figure 5

Influence of animal age on the size of the stem-cell niche. (a) and (b) HF bulges. Note that bulge is a very prominent structure (arrow) in the foetal skin HFs ((a) from Google images) but not morphologically distinguishable (arrow) in the adult skin HFs (b). (c) and (d) AU pedicles. Note that pedicles are the longest (arrow; hence, the PP is the largest in area) in the first year of deer’s life (c) but totally disappear (arrow) in the mature stags (d).