HP - C17Notes - The Endocrine System.doc - Human Physiology Notes Chapter 17 – The Endocrine System Cell – to – Cell Communication Cells

HP - C17Notes - The Endocrine System.doc - Human Physiology...

This preview shows page 1 - 2 out of 8 pages.

Human Physiology Notes Chapter 17 – The Endocrine System Cell – to – Cell Communication Cells communicate using chemical and electrical signals Electrical signal = change in membrane potential Chemical signal = molecules present in ECF affect target cell How can cells communicate? Gap junctions – connexins form cytoplasmic bridges that allow chemical and electrical communication between adjacent cells Gap junction present in most cell types; most known in heart muscle cells Contact-dependent signals – cell adhesion molecules (CAMs) connect and influence an adjacent cell by exchange of surface membrane molecules Cell communication during growth and development Local communication – signal molecules present in ECF affect a nearby target cell Paracrine signal (Silverthorn Glossary) – chemical secreted by a cell that acts on cells in immediate vicinity o Histamine released from damaged cells induces capillary tissue to become more permeable, allowing entry of WBCs and ABs Autocrine signal (Silverthorn Glossary) – local chemical signal that acts on the cell that secreted it Long-distance communication Chemical signals (i.e. hormones) transferred to target cell via blood Electrical signals transferred via action potential Types of signal molecules (all directly from Silverthorn Glossary) Neurotransmitter – chemical signal released by a neuron that influences the neuron’s target cell Neurohormone – hormone that is produced and secreted (into blood) by a neuron Hormone – chemical signals released (into blood) by endocrine glands Cytokine – regulatory peptides released by all nucleated cells that affect cell development, differentiation, and the immune response Signal Pathways General Characteristics of Signal Pathways Signal molecule binds to specific receptor Ligand binding activates receptor Receptor activates intracellular signal molecule(s) Signal molecule Initiates protein synthesis Modifies existing proteins Receptor proteins located on cell membrane or within cell Lipophilic signal molecules -steroid hormones and amine hormones (thyroid hormones) Diffuse through cell membrane Bind to receptors in cytoplasm or in nucleus Activate transcription (and translation) of regulatory protein Slow response Lipophobic signal molecules - peptide hormones, amine hormones (catehcholamines) Cannot diffuse through cell membrane Bind to receptors on the cell membrane, activating second-messenger Second messenger activates regulatory protein already present in cell Fast response Types of Membrane Receptor Proteins – lipophobic Signal transduction (Silverthorn Glossary) – transmission of information (for homeostasis) from one side of a membrane to the other via membrane proteins Chemically gated ion channels Ligand-channel binding opens or closes channel o
Image of page 1
Image of page 2

You've reached the end of your free preview.

Want to read all 8 pages?

  • Fall '16
  • Dusti Sloan

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Stuck? We have tutors online 24/7 who can help you get unstuck.
A+ icon
Ask Expert Tutors You can ask You can ask ( soon) You can ask (will expire )
Answers in as fast as 15 minutes
A+ icon
Ask Expert Tutors