Fig. 1.4.3.03. A dendritic filopodium (F) extends from the shaft of a dendrite (D) containing numerous ribosomes (arrows). Note the resemblance of the dendritic filopodium to the filopodium of an axonal growth cone (A). Both have a dark, grainy cytoplasm characteristic of a dense actin matrix. Scale = 1 µm. (6 day-old rat, hippocampus area CA1.)