PHYSIOLOGY

• what is cell signalling

  the molecular mechanisms by which target cells detect and respond to external stimuli and send messages to other cells
• what are receptors

  protein structures suspended within the membrane which respond to specific signals
• what are ligands

  signalling molecules that bind to receptors
• what do problems with signalling cause

  disease e.g. diabetes, cancer, inflammation, immunodeficiency
• what is signal transduction

  conversion of an impulse or stimulus from one physical or chemical form to another
• direct space

  • connexions form pores or gap junctions directly through the cell membrane
  • contact-dependent signalling
• paracrine signalling

  • signalling molecule released by a cell to an adjacent cell via extracellular fluid
  • secreted molecules are local mediators