• Imagine that you have a friend in Memphis. You would like to send this friend a message.

Your friend doesn’t have a land-line phone.

Your friend doesn’t have a cell phone.

Your friend doesn’t have an internet connection.

Your friend lives an impoverished existence.

You on the other hand, have rich resources, including a bottle, a

cork, and a piece of paper with your message on it.

What could you do to increase the likelihood that your friend in Memphis would get your message?

Fig. 4.1. Types of receptors

Fig. 4.13. Ligand-gated ion channel. Where have we seen this?

Fig. 4.14.Receptor-enzymes

Fig. 4.19.Signal transduction via G-protein-coupled receptors

What do these three mechanisms have in common?

Contrast them to the mechanism shown in the following slide.

Fig. 4.11Signal

transduction by

intracellular receptors.

Fig. 4.32.Connections between the

hypothalamus and the posterior

pituitary.

Fig. 4.33Connections between the

hypothalamus and the anterior

pituitary.