[Anatomy and physiology of the lymphatic system]

The lymphatic capillaries, elements of the micro-circulatory unit, are formed within the interstitial tissue to which they are fixed. The convergence of the interstitial capillaries creates collectors which become increasingly large and valved. Distributed along the main vascular tracts for the deep network and along the subcutaneous for the superficial, anastomoses exist between the deep and superficial networks and others form in certain pathological conditions. It is the liquid impregnation of the interstitial tissue which triggers off the filling of the lymphatic vessel. Lymph progresses thanks to: the presence of valvules on the collectors, the arterial pulse, the muscular contractions, the pressure of adjoining tissues, and to thoracic aspiration. Nervous and hormonal phenomena are responsible for the formation and progression of the lymph.