11. Because "'lymph sacs "'form from the venous system , they typically contain red blood cells. 12. In contrast, pressures in the venous system are constant and rarely exceed 10 mmHg. 13. Within the cortex, nephrons are organized around central veins of the efferent venous system . 14. Anterior spinal veins fall into the intradural network of the "'vertebral venous system " '. 15. The fluid is eventually absorbed into the venous system . 16. The venous system arises from three bilateral veins during weeks 4 8 of embryogenesis. 17. Embolized fat travels through the venous system to the lungs and can occlude pulmonary capillaries. 18. In microgravity, the cranial venous system has been put into minimal outflow and maximal obstruction. 19. "With meditation, it's like you're giving your venous system a chance to regroup and revitalize ." 20. The portal venous system is a series of veins or venules that directly connect two capillary beds.