These are softer and more flexible, consisting of a small rubber tip with tiny projections. (petsforpatriots.org)
Early in pregnancy, these trophoblasts invade the uterine wall and later develop a complex network of tiny projections called villi, which contain fetal blood vessels. (sciencemag.org)
Further, in another brain region, the hippocampus, neurons are undergoing changes of another sort, leading to increases in the concentration of tiny projections on the surface of dendrites, called dendritic spines. (scientificamerican.com)