The lymphatic system of man and mammals is in close functional interaction with the blood circulation and is connected with it by means of large lymph trunci in the venous system of the heart region. So the lymphatic vessels are part of a comprehensive circulatory system serving the substance exchange within the body and between the body and environment. Whereas the blood vessel system is closed, with continuous circulation of the blood and with capillaries by which small molecules can be quickly exchanged, the lymphatic vessel system in its initial region serves for the uptake of fluid, larger molecules, and cells from the interstitium, which cannot be reabsorbed by the blood vessels. Depending on their function, different morphological parts of the lymphatic vessel system exist: initial lymphatics, precollec-tors, collectors, and lymph stems (Table I). All these vessels are lined with a functionally adapted endothelium. Whereas the endothelium of the collectors and trunci is similar to the endothelium of the venous system, the endothelium of initial lymphatics and precollectors displays a special differentiation.
Was this article helpful?
This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.