GENERAL HISTOLOGY

Detailed explanation-1: -When pressure is greater in the interstitial fluid than in lymph due to accumulation of interstitial fluid, the minivalves separate slightly like the opening of a one-way swinging door so that fluid can enter the lymphatic capillary.

Detailed explanation-2: -Lymphatic vessels collect and filter lymph (at the nodes) as it continues to move toward larger vessels called collecting ducts. These vessels operate very much like your veins do: They work under very low pressure, have a series of valves in them to keep the fluid moving in one direction.

Detailed explanation-3: -Valves are found in larger lymph vessels and collecting vessels and are absent in the lymphatic capillaries. The valves is to prevent backflow of fluid, so that lymph eventually flows forward instead of falling backwards.