Forms of Intercellular Communication

1. Endocrine: secretion of a hormone by one cell with transmission via the blood, lymph, or intercellular fluid to a second, target, cell.
2. Paracrine: secretion of a hormone by one cell with transmission via intercellular fluid to a second, nearby cell.
3. Autocrine: secretion of a hormone by one cell with reception and response by the same cell.
4. Pheromonal: secretion by one organism and sensation and response by a second.