1. Connect!  Make a quick sketch of the Earth as a ball.  Add satellite dish, and radio towers, electric/phone poles, phone towers… any structure that sends poles, phone towers… any structure that sends or receives information. or receives information.  Why do these structures stick up from the surface of the Earth? surface of the Earth?  Sketch a diagram of the structure of the cell membrane.  Add to the diagram to indicate how cells could send/receive info.  What are the structures called that receive info?

2. Recognizing Signals  cells are able to receive messages due to the cell membrane which has special receptor molecules

3.  these receptors have specific shapes which correspond to chemicals such as hormones that send messages to target cells  Cells not meant to receive a specific message simply do not have the corresponding receptor in their cell membranes

4. Cell Receptors Surface carbohydrates on cells serve as points of attachment for other cells, infectious bacteria or viruses, toxins, hormones, and many other molecules. Surface carbohydrates on cells serve as points of attachment for other cells, infectious bacteria or viruses, toxins, hormones, and many other molecules.

5. Lymphocytes, a type of white blood cell, recognize foreign invaders by using receptors. Lymphocytes, a type of white blood cell, recognize foreign invaders by using receptors.

6. Hormones influence target cells by binding to receptors, which then influence the nucleus to direct cell activities in a certain way. Hormones influence target cells by binding to receptors, which then influence the nucleus to direct cell activities in a certain way. NUCLEUS HORMONE TARGET CELL MEMBRANE MESSAGE

7.  For example, the hormone FSH is sent from the brain all over the body of a woman through the blood. Only the cells with the correct receptors (in this case the cells of the ovaries) receive this message to mature eggs. Pancreas cell Stomach cell Brain cell Ovary cell

8. Chunk!  How do cells receive messages?  How do the receptors work?  What is a “target” cell?  Name some things that cells have receptors for.  How do hormones work?  Give a specific example of a hormone and its target cell.

9. Images  Cell membrane - http://library.thinkquest.org/C004535/media/cell_membrane.gif http://library.thinkquest.org/C004535/media/cell_membrane.gif  Receptor - http://www.unisa.edu.au/iwri/futurestudents/phdprojects/interf4.jpg http://www.unisa.edu.au/iwri/futurestudents/phdprojects/interf4.jpg  Virus and lymphocyte - student.ccbcmd.edu/.../gensteps/u3fg2g.html  Rest of images are self-generated