The document contains a schematic diagram including a simple neural pathway, a neurohormone pathway, a neuroendocrine pathway and a simple endocrine pathway. The simplified drawing is intended to be color-coded to highlight both the unique and overlapping features of the four pathways. There are two versions of the diagram: one is smaller and includes a labeled Venn diagram, the other is larger and is more easily colored. I typically introduce this worksheet after students have learned about the nervous system and the basics of cell signaling (e.g. they know about membrane receptors). This enables students to apply prior knowledge to gain an initial understanding of new content. Students may also use the schematic diagrams to guide their learning of specific examples for any one of the pathways (e.g. milk release or blood sugar regulation). The document includes an answer key in the form of a colored version and a completed Venn diagram.