Figure 35.2: Chemical Signaling Occurs over a Broad Range of Spatial Scales (A) Cells communicate with neighboring cells in a tissue via molecules called paracrines. (B) Neurons have long processes (axons), at the ends of which they release molecules called neurotransmitters to communicate across synapses with target cells. (C) Endocrine cells secrete molecules called hormones that can travel long distances by circulating in the blood. (D) Animals give off molecules called pheromones that can communicate specific information (such as their sex) over very long distances to other members of their species.