Physio Ch 6 Homeostasis & Communication

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Physio Ch 6 Homeostasis & Communication
2014-02-22 04:15:47
Human Physiology Dorner Silverthorn
study guide questions
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  1. What are target cells (targets)?
    Cells that respond to electric signals and chemical signals
  2. List and describe the basic methods of cell-to-cell communication. Fig. 6.1
    Local Communication

    • Gap Junction signal-form direct cytoplasmic connects between adjacent cells
    • -protein channel made of connexon.
    • -only way an electric signal can pass from cell to cell
    • -located in heart muscle, some types of smooth muscle, lungs, liver, and neurons of the brain.
    • Contact Dependent signal-interaction between two cells through a membrane molecule.
    • -Cell adhesion molecule CAMs
    • -occurs in immune sys. and during growth and development 

    • Autocrine signal-act on the same cell it is secreted on.
    • -sometime autocrine do both auto- and paracrine duties.

    Paracrine signal-secreted by one cell and diffuse to adjacent cells
  3. What kind of signals pass through gap junctions?
    electrical signals
  4. What proteins create gap junctions?
    connexons(protein channel)
  5. Where would you find gap junctions?
    heart, lungs, neurons on the brain
  6. Give some examples of contact-dependent signaling. What are some of the proteins involved?
    • -occurs in the immune system and during growth and development
    • -when a nerve cell from the central axis of the body tells a limb to grow.
    • -cell adhesion molecule(CAMs) act as receptors for cell to cell communication and hold the cell to the cytoskeleton
  7. Distinguish between paracrine and autocrine signals.
    • -paracrine sends a signal to the adjacent cell as well as the same cell that was signaled
    • -autocrine is a chemical signal sent the same cell that it was secreted on
    • -autocrine sometimes do both jobs
  8. How do chemical signals secreted by cells spread to adjacent cells? What limitation does this present?
    • -the chemical composition changes affecting the nearby cells
    • -limited to local communication
  9. Give some examples of local signal molecules.
    • cytokines
    • eicosanoids
    • histamines