Imagine that you were lucky to be selected for an internship at the National Space Biomedical Research Institute in Houston, Texas.

Imagine that you were lucky to be selected for an internship at the National Space

Biomedical Research Institute in Houston, Texas. Part of your job is to monitor

the health of the astronauts for the National Aeronautics and Space

Administration (NASA) before, during and after a space mission. By chance, your

time in the lab corresponds with the return of an American astronaut from the

International Space Station. She just spent 171 days in the space station and is

now getting back to her research studies on earth. Unfortunately, it was

discovered that she would have to go through at least 3 weeks of physical

therapy. You learned from reading her physical health report that she lost 30% of

her skeletal muscle mass. Most of it occurred within the last 2 months of the

mission in space. The normal muscle loss during results from disuse, yet she

followed all the exercise programs NASA requires. Your job is to assist the

research team in investigating her problem. At the end of the chapter, you will be

asked to determine the most likely cause of her accelerated loss of muscle mass.