Do all lymphatic vessels have valves?
apple guava – The answer is NO, not all lymphatic vessels have valves, and sometimes the valves do not function well. The lymph capillaries do not have valves, but instead drain the lymph to larger contractile lymphatics, which have valves as well as smooth muscle walls. These are called the collecting lymphatics. As the collecting lymph vessel accumulates lymph from more and more lymph capillaries in its course, it becomes larger and is called the afferent lymph vessel as it enters a lymph node. Here the lymph percolates through the lymph node tissue and is removed by the efferent lymph vessel. An efferent lymph vessel may directly drain into one of the (right or thoracic) lymph ducts, or may empty into another lymph node as its afferent lymph vessel. Both the lymph ducts return the lymph to the blood stream by emptying into the subclavian veins. The functional unit of a lymph vessel is known as a lymphangion, which is the segment between two valves. Since it is contractile, depending
