KJ

Chapter 2

  • Signals are constantly sent and recieved to maintain homeostasis
    • Organism → Communication → Cell → Communication → Organism
    • communication
    • first and second messengers
    • hormones
    • growth factors
    • cytokines
    • neurotransmitters
    • action potenial
    • cell responses
    • secretion
    • contraction
    • metabolic
  • Communication modes
    • probably not all of the modes we have
    • endocrine
    • hormones
    • takes longer
    • travels in bloodstream
    • paracrine
    • different types of cells, but next to each other (diffusion)
    • controls development and differentiation
    • growth factors, cytokines, vasoactive agents, neurotransmitters
    • autocrine
    • same type of cells next to each other
    • basically paracrine, but with the same type of cell
    • juxtacrine
    • next to each other, giving handshakes
    • integral membrane proteins
    • B and T cels
    • adhesion molecules, membrane-bound cytokines, extracellular matrix
    • synaptic
    • specialized paracrine
    • neurotransmitters
  • Signal Pleiotropy
    • one signal has many meanings
    • different cell types and different receptors/proteins do different things with the same signal
  • Early and Late Responses
    • Early (fast): just have to modify a protein (seconds)
    • Late (slow): requires transcription/translation (min-hour)
  • Vocab Review
    • Ligand: binds to a receptor
    • Agonist: binds to and activates receptor
    • Antagonist: binds to and inhibits receptor
    • Receptor: binds ligand and transduces signal
    • transduction/transduce: to change the form of
    • Second messanger: ligand produced (cAMP) or relased (Ca2+) into cytosol that carries the signal around the cell
    • Inverse agonist: binds to receptor and inhibits its intrinsic activity (keeps it inactive)