What relationship exists between NIH, CDC, US Public Health and the FDA?
The U.S. Public Health Service started as a very modest organization back in 1798. The organization was first known as the Marine Hospital Service. President John Adams signed into law an act providing for the care and relief of seamen who were sick or disabled (Sultz and Young, Pg, 343.). As time would pass, the organization would restructure and reorganize itself. By doing so, it would eventually develop programs that would include activities such as medical and social science research (NIH), assurance of food and drug safety and effectiveness of pharmaceuticals, biologic products, and medical devices (FDA), and infectious disease prevention and control (CDC).
These systems are interdependent and contribute to the United States populations overall health and safety. Public health activities are executed at many levels from local to national to global. An example of interdependency between a few programs would be how Dr. Margaret Hamburg (2011) discusses the interaction between the FDA, the CDC and other agencies. They all cooperated with each other during the H1N1 influenza virus breakout in 2010.The organizations and agencies devoted to public health at these different levels share many of the same functions including disease surveillance, policy development, and provision of access to health care.

References
Sultz, H. A. & Young, K. M. (2011). Health care USA: Understanding its organization and delivery, 7th Edition. Sudbury, MA: Jones & Bartlett Learning, LLC. p. .
Food and Drug Administration (FDA). Available at: http://www.fda.gov/default.htm. Accessed June 14, 2013.
The Role of Nongovernmental Organizations. International Information Programs U.S. Department of State. Available at: http://usinfo.state.gov/products/pubs/principles/ngos.htm. Accessed
June 14,