Lymphatic vessels: pressure- and flow-dependent regulatory reactions.

This chapter discusses the current status of knowledge on basic pressure/stretch- and flow/shear-dependent regulatory reactions of contracting lymphangions in lymphatic vessels. The balance of passive and active lymph pumps is discussed; the data on pressure measurements in different lymphatic nets of several species are provided. The characteristics of typical changes in lymphatic contractility to the increases in transmural pressures are described and discussed, as is the role of pre-existing distension in initiation of lymphatic contractions. The up-to-date status of knowledge on flow-dependent adaptive reactions of contracting lymphangions is provided with detailed characterization of the influences of imposed and contraction-generated flows on lymphatic contractility. The interaction between extrinsic and intrinsic flows in regulation of lymphatic contractility is considered.