The Spleen in Spaceflight

Studies related to splenic physiology during spaceflight have focused on its immune function. However, the internal jugular deep vein thrombosis discovered during a recent space mission spotlighted that the circulatory and hemostatic physiology of spaceflight is not yet well understood and likely involve not only aspects of hemodynamics, but also the output of the reticuloendothelial system (RES), which effects homeostasis via RBC clearance, mediates platelet formation and storage, blood
viscosity, and thrombotic functions. On Earth, the spleen plays an active role in the RES and hemostatic physiology. What role might the spleen play in circulation hemostatic physiology during spaceflight and what alterations in its function should be
expected in the microgravity environment?

In reviewing the literature to date we sought to understand:
- Splenic effects on RBC clearance, anemia, and hemostasis
- Splenic and splanchnic contributions to arterial and venous blood storage
- How splenic and splanchnic physiology may alter in microgravity