Fluid exchange between capillaries and the interstitial fluid. takes place between the blood and interstitial fluid across the thin endothelial walls of the capillaries. blood pressure drives fluid out of the capillaries, blood proteins pull fluid back in the capillaries by osmotic pressure. Difference in osmotic pressure and blood pressure drives fluids out of capillaries at the arteriole end and into capillaries at the venule end.
Premarket approval (PMA) is the FDA process of scientific and regulatory review to evaluate the safety and effectiveness of Class III medical devices.remarket approval (PMA) is the FDA process of scientific and regulatory review to evaluate the safety and effectiveness of Class III medical devices.
A Class III device that fails to meet PMA requirements is considered to be adulterated under Section 501(f) of the act and cannot be marketed. Premarket approval requirements apply differently to preamendments devices, postamendments devices, and transitional Class III devices.anufacturers of Class III preamendments devices are not required to submit a PMA until 30 months after the promulgation of a final classification regulation or until 90 days after the publication of a final regulation requiring the submission of a PMA, whichever period is later.