6A

• Homeostasis


  The maintenance of a relatively stable internal environment in the body despite changes in the external environment
• Stimulus-Response Model


  A model that describes how a system responds to a stimulus
• Positive Feedback System


  A stimulus-response process in which the response increases the stimulus
• Negative Feedback System


  A stimulus-response process in which the response counters the stimulus
• Stimulus


  An event or molecule that can initiate a response
• Receptor


  A structure that detects a signal or external change, usually a protein
• Modulator


  Location where information from receptors is sent to and compared to a set point, and where molecules altering the functioning of an effector are released. Also known as the processing centre
• Effector


  A molecule, cell, or organ that responds to a signal and produces a response
• Hormone


  A signaling molecule released from endocrine glands that regulates the growth or activity of target cells
• Response


  The action of a cell, organ, or organism caused by a stimulus
• Transduction


  The series of events that occur after the reception of a signal which results in the generation of a response