Capillary exchange is the transport of substances between blood and interstitial fluid across the capillary wall, occurring by diffusion, vesicular transport and filtration.
Filtration is governed by Starling's forces, the hydrostatic and osmotic pressures across the capillary wall.
Diffusion: gases, nutrients, hormones; the common method in most tissues.
Vesicular transport (transcytosis): for large lipid-insoluble substances.
Filtration: bulk fluid movement via Starling's forces.
In the liver, sinusoidal capillaries allow large proteins such as fibrinogen and albumin to diffuse into circulation directly.
Vesicular transport across endothelial cells is also called transcytosis: dissolved plasma proteins are taken up by endocytosis on one side and discharged by exocytosis on the other.