Quick Facts
Smooth muscle is a type of muscle without transverse striations in its constituent fibers; it is found in the walls of the viscera and vessels and in the dermis and is not under voluntary control (Dorland, 2011).
Structure/Morphology
Afferent lymphatic vessels contain one or more layers of smooth muscle cells. Efferent lymphatic vessels contain several layers of smooth muscle (6). It has both sympathetic and parasympathetic innervation, therefore, by innervating the smooth muscle cells in the wall of the vessel, they are capable of producing rhythmic contraction. This rhythmic contraction helps the return of lymph back to the venous system, which is also aided by external movements, such as muscle movements and movements from the arteries and veins. This collectively is known as lymph propulsion (7).
Function
The smooth muscle layer of the vessel aids the spontaneous contraction of the lymph vessels, thus, driving the propulsion of lymph through the vessels.
References
Dorland, W. (2011) Dorland's Illustrated Medical Dictionary. 32nd edn. Philadelphia, USA: Elsevier Saunders.
Margaris, K. N. and Black, R. A. (2012) 'Modelling the lymphatic system: challenges and opportunities', J R Soc Interface, 9(69), pp. 601-12.
Rovenska, E. and Rovensky, J. (2011) 'Lymphatic vessels: structure and function', The Israel Medical Association Journal, 11, pp. 762-768.
