Paul Andersen discusses cell communication. He begins by explaining how he communicates with other individuals using various forms of electronic communication. He them explains how cells communicate when the distance between them is big, small, and zero. He explains how antigen presenting cells pass information on antigen structure by touching in the immune response. He explains how neurotransmitters are used to transfer and manipulate nerve signals. And he finally explains how the endocrine system sends messages throughout the body.