Within 150-180 worlds elaborate and use in text citations and references

Within 150-180 worlds elaborate and use in text citations and references. 

What is a question that researchers in health psychology might want answered about the function of three of the biological systems? You may choose from the cardiovascular, digestive, respiratory, endocrine, digestive, immune or reproductive systems. Explain the role of the three systems that you chose.

Let's take this discussion question one step further.  Suppose you are a researcher.  What is a research question you would like answered?  Use one of the systems described above and briefly describe your study and what you expect to find in terms of results.