Peripheral circulation
Exchange mainly by diffusion
bulk flow, 20L lost, 17L regained each day
3L remaining
lymphatic system drains that fluid
accumulation of excess fluid causes oedema
oedema could be due to
-raised CVP due to ventricular failure
-lymphatic obstruction due to filariasis, surgery
-hypoproteinaemia due to nephrotic syndrome, liver failure, malnutrition
-increased capillary permeability, inflammation e.g. rheumatoid

MAP is that driving force pushing blood through your system circulation, if MAP is low you will get decreased perfusion through vascular beds
central intrinsic mechanisms concerned with meeting needs of individual tissue
central extrinsic mechanisms concerned with ensuring total peripheral resistance (and therefore MAP) of the whole body stays in the right ball park