There are two parts to today’s lab:

With a partner, read through the 8 scenarios in the worksheet and identify the various parts of the pathway involved. Then, determine whether it is a negative or positive feedback loop. The following definitions should be helpful:

• Stimulus: a detectable change in the internal or external environment
• Sensory receptor: structures or cells that detect stimuli
• Integrator: compares any detected changes to at set point (“normal” condition), and sends a signal to trigger a response when needed
• Effector: a tissue or organ that carries out an action and produces an effect
• Response: the change in state or activity as a result of the stimuli and subsequent pathway
  • The effector is the proximate cause of the response
  • The stimulus is the distal cause of the response

Using the PhysioEx virtual lab platform, complete the following two activities from Exercise 4:

• Activity 1: Metabolism and Thyroid Hormone
• Activity 3: Hormone Replacement Therapy