The Lymphatic/Immune System and Its Disorders
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
To move the lymph along its course, the system incorporates a pumping mechanism. All lymph vessels contain lymphatic valves, also known as valvulae lymphatica (singular: valvula lymphaticum). As a lymphatic vessel fills with lymph, it contracts in response to being stretched. The contraction forces the lymph past the lymphatic valve and into the next section of the vessel, and the valve closes from the back pressure as that new section begins to contract. Additionally, pressure is applied to the lymphatics by muscle movement, and even arterial pulsations during exercise compress the lymphatics, moving lymph along the channel. In the initial lymphatics, contraction or pressure causes the channels between overlapping endothelial cells to close, and the anchoring ligaments squeeze the lymphatic capillary as the surrounding cells move.
Structure of Initial and Collecting Lymphatic Vessels
Waldemar L. Olszewski in Lymph Stasis: Pathophysiology, Diagnosis and Treatment, 2019
Two basic functions exerted by the lymphatics prevail: one is the uptake of tissue fluid as a process of lymph formation by the vascular structures at the beginning of the lymphatic system. The other is the efficiency to drain and to propel the lymph forward by an active pumping mechanism due to the lack of a heart action. The lymphatic vessels to some extent resemble blood vessels. Consequently, initial lymphatics have been frequently compared with blood capillaries and the collecting channels with veins. On the basis of new electron-optical findings and experimental studies, a more differentiated consideration seems to be necessary, which stresses the special morphological features of the lymphatics and their related functions. The new approaches in morphology also challenge us to reconsider the old theories of lymph formation, or at least, to supplement them concerning some points. Whether an “open or closed” lymphatic system exists against the tissue spaces in lymphology has been questioned for a long time; this is being discussed again because of recent vital-microscopic and scanning electron microscopic findings. Finally, with the widening of our knowledge in basic morphology of lymphatic structures, pathological phenomena, such as edema and lymph stasis especially being treated in this book, become better understandable.
Autopsy Cardiac Examination
Mary N. Sheppard in Practical Cardiovascular Pathology, 2022
The heart is supplied by a rich plexus of lymphatics. The lymphatic channels run along with the veins and drain the lymph to the pulmonary hilar lymph nodes and also directly into the thoracic duct and the left lymphatic channel. As part of the circulatory system, lymphatic vessels have particular functions in fluid homeostasis, lipid absorption, immune cell trafficking and causative agent filtration. The lymphatic vascular system consists of a compact network of blind-ended, slight-walled lymphatic capillaries and collecting lymph vessels that drain exudative protein-rich fluid from the majority of tissues that transport the lymph by way of the thoracic duct to the venous circulation. Several lymphatic endothelial markers, such as vascular endothelial growth factor receptor 3 (VEGFR-3), lymphatic vessel endothelial hyaluronic acid receptor-1 (LYVE-1), prospero-related homeobox-1 (Prox-1) and podoplanin (D2-40) are widely used in labelling lymphatics (Fig. 1.16).
Lymphatic targeting for therapeutic application using nanoparticulate systems
Published in Journal of Drug Targeting, 2022
Nidhi Singh, Mayank Handa, Vanshikha Singh, Prashant Kesharwani, Rahul Shukla
The lymphatic system was first recognised by Gasparo Aselli in the seventeenth century as per ancient text reports. It was later in the eighteenth century when various aspects of lymphatic system including its anatomy, got its attention and significance. Vascular system is further compartmentalised into lymphatic system that encompass different convoluted web of channels and hold a clear liquid termed lymph. Lymphatic system is composed of lymphatic duct, lymphatic capillaries, lymphatic vessel and some lymphatic organs including spleen and lymph node. Lymphatic vessels carry a clear watery fluid lymph, and white blood cells. Furthermore, lymphatic system is widely distributed in other parts of body in the form of lymph nodes, which is present in the neck, chest, armpit, groyne, abdomen. Lymphatic system maintains homeostasis and protection of the body tissues against different bacterial and viral infection by the mechanism of filtration. The lymphatic system not only filters the elements from lymph but avoid the first-pass hepatic metabolism of drugs directly via intestinal uptake [1]. This property plays an important role in tissue defense against infections by promoting the lymphocytic activity which in turn provides immunity or resistance. As mentioned, one of the major roles of the lymphatic system is to maintain water homeostasis in the body by recurring fluids present outside the body and oozing out into the blood circulation. It also enhances the absorption of antibiotics, water-insoluble vitamins, long-chain fatty acid and cholesterol ester.
Survival prediction in patients with cutaneous melanoma by tumour lymphangiogenesis
Published in Acta Clinica Belgica, 2020
Zorica Špirić, Milka Vještica, Mirela Erić
In conclusion, we found that ulceration plays a part in promoting intratumoural lymphangiogenesis. Our study finds significant LVD-related differences in survival of patients with cutaneous melanoma. Out of all clinical-pathological parameters and quantitative parameters of melanoma lymphangiogenesis, intratumoural LVD is the most significant predictor of melanoma-specific survival, while only peritumoural LVD has a significant impact on both disease-free survival and on melanoma-specific survival. We have completed quantification of the formed lymphatic vessels network. The most comprehensive data may be gained through further research of the active, ongoing lymphangiogenesis, with quantification of lymphatic endothelial cells in proliferation, with the use of proliferation marker Ki-67 and dual staining D2–40/Ki-67. Prospective multi-institutional studies in the future are needed to confirm the prognostic significance of lymphangiogenesis parameters.
Engineering drug delivery systems to overcome mucosal barriers for immunotherapy and vaccination
Published in Tissue Barriers, 2020
Jacob C. McCright, Katharina Maisel
More recently, technologies have emerged that indirectly target lymph nodes by targeting lymphatic transport.120 The rationale behind targeting the lymphatic vessels is due to the transport functions of these vessels. Cells, fluids, protein, and small molecules are transported from peripheral tissues to the draining lymph nodes where adaptive immune responses are formed. Convective fluid flow in the interstitium drives fluid and molecules toward lymphatic vessels.120 This fluid flow becomes increasingly important with increased molecular size, as the opposing movement toward blood capillaries by diffusion decreases for larger molecules.120 At the same time, the extracellular matrix holding together the interstitium needs to be traversed, so particles need to be small enough to get across this extracellular matrix and reach lymphatic vessels and their downstream dLNs.
Related Knowledge Centers
- Adventitia
- Extracellular Fluid
- Lymph
- Smooth Muscle
- Endothelium
- Lymphatic System
- Circulatory System
- Blood Vessel
- Capillary
- Lymph Capillary