1.1.5.3　Lymphatic vessels

There are relatively fewer lymphatic vessels in the skin which are generally difficult to identify in normal skin tissues.The lymphatic network of the skin is parallel to several major vascular plexuses.The blind end of the skin capillary lymphatic vessels starts in the dermal papilla layer and gradually merges into a thicker wall with valve-like lymphatic vessels，forming a shallow lymphatic network under the papillary layer and the lymphatic network of the dermis.Then，they join and connect to the larger lymphatic vessel in deep skin and subcutaneous tissues，and subsequently enter the systematic circulation of the whole body.The structure of lymphatic vessels is the same as that of veins，and can also be divided into three layers.Different from the veins，the tube walls of lymphatic vessels are thinner，there are no red blood cells in the cavity，the smooth muscle fibers in the media are arranged irregularly，and the adventitia is thicker.The structures of lymphatic capillaries and capillaries are also the same.The difference is that the lumens of lymphatic vessels are irregular and sinus-shaped，and there are no surrounding cells（namely Rouget cells）.(https://www.daowen.com)