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.
The FDA PMA approval process is more complex and time-consuming than 510(k) premarket notification, and requires considerable preparation and resources. There are five general components to the FDA PMA approval process for medical devices: 1  Pre-Submission (pre-sub).2  Investigational Device Exemption (IDE).3  Premarket Approval.here are five general components to the FDA PMA approval process for medical devices: 1  Pre-Submission (pre-sub). 2  Investigational Device Exemption (IDE). 3  Premarket Approval.