What does cAMP do?
Signals like cAMP are generated inside cells in response to certain types of external events that are detected at the cell surface. cAMP acts as a cellular messenger that relays the external events to the correct location within the cell to initiate the required action. Just like when you use your TV remote (external event) to turn up the volume and make the speaker inside the TV (internal response) generate more sound.
The cell interior is like a factory floor that is packed full of different pieces of cell signalling machinery, each of which does a key job that needs to be regulated. Only certain of these processes are regulated by cAMP