Communication between cells is required to coordinate their diverse activities. Cells may secrete molecules that spread locally to nearby cells or that are carried in the bloodstream to cells throughout the body. Nerve cells transmit electrochemical signals that carry information much more rapidly than is possible by diffusion or blood flow.
For Grades: 9-12
Learning Goal 3
Human thinking involves the interaction of ideas, and ideas about ideas. People can produce many associations internally without receiving information from their senses.