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.
Lymph Node
Joseph Kovi, Hung Dinh Duong in Frozen Section In Surgical Pathology: An Atlas, 2019
As has been already noted, the collecting lymphatic vessels, called the afferent lymphatic vessels, release the lymph into the subcapsular sinus. The lymph leaves the node through a single efferent lymphatic vessel at the hilus of the lymph node. Lymph nodes draining cancerous organs, axillary nodes in breast cancer, peribronchial nodes in lung cancer, and perigastric nodes in carcinoma of the stomach remove neoplastic cells from the lymph through what is actually a filtration process. Because the first tumor cells reach the lymph node via the afferent lymphatics, it is obvious that the first tumor cells which metastasize into the node will be found in the subcapsular sinus. If a lymph node has been submitted for frozen section study to rule out metastatic cancer, the subcapsular sinus must be examined very carefully for the presence of neoplastic cells. Quite often the only evidence of metastasis is the discovery of a few tumor cells in the subcapsular sinus (Figure 89).
Histology of the mesentery
John Calvin Coffey, Rishabh Sehgal, Dara Walsh in Mesenteric Principles of Gastrointestinal Surgery, 2017
intermediate between mesothelial and mesenchymal cells [23,25,26]. It is feasible that mesenchymal cells within these clusters are derived from overlying mesenteric mesothelium. The connective tissue lattice also houses a lymphatic network (Figure 4.7b and c). Lymphatic vessels are identifiable in the submesothelial connective tissue monolayer as well as in septations. The frequency with which lymphatic vessels are identified varies (though not significantly) between mesenteric regions. In submesothelial connective tissue, lymphatic vessels measure 10.2 ± 4.1 µm in diameter and have an average radius of diffusion of 174.72 ± 97.68 µm. This means that a lymphatic vessel occurs every 0.17 mm (Figure 4.7b and c). Lymphatic vessels also occur in Toldt's fascia where they measure 4.3 ± 3.1 µm in diameter and have a radius of diffusion of 165.12 ± 66.26 µm. Collectively, a rich lymphatic network occupies all levels of the mesenteric connective tissue lattice and may be vulnerable during surgery [26].
Microspheres Encapsulating Immunotherapy Agents Target the Tumor-Draining Lymph Node in Pancreatic Ductal Adenocarcinoma
Published in Immunological Investigations, 2020
Booyeon J. Han, Joseph D. Murphy, Shuyang Qin, Jian Ye, Taylor P. Uccello, Jesse Garrett-Larsen, Brian A. Belt, Peter A. Prieto, Nejat K. Egilmez, Edith M. Lord, David C. Linehan, Bradley N. Mills, Scott A. Gerber
Whole-mount microscopy was performed by excising tumors and lymph nodes from mice at endpoint. The afferent lymphatic vessel was dissected intact with the TDLN. Tissues were then placed on glass slides with two drops of PAB (1 L PBS, 1 g sodium azide, 10 g BSA). A coverslip was placed on top of the tissue and gently pressed down, and excess PAB was removed by blotting. The tissue was then visualized via bright field and fluorescence microscopy of the same field of view. For confocal microscopy, tissues were prepared as above and the following antibodies were used for identification of blood and lymphatic vessels: CD31-BV421 (390, BioLegend) and LYVE-1-AF-488 (ALY7, eBioscience). Surface markers were stained for 30 min at 4°C in the dark and washed two times with 2 mL of PAB for 2 min prior to mounting on slides. Images were captured using a Nikon A1 R HD laser scanning confocal microscope using the high-speed resonant and galvano (non-resonant) scanner. All images were analyzed using ImageJ.
The application of indocyanine green (ICG) and near-infrared (NIR) fluorescence imaging for assessment of the lymphatic system in reconstructive lymphaticovenular anastomosis surgery
Published in Expert Review of Medical Devices, 2021
Albert H. Chao, Steven A. Schulz, Stephen P. Povoski
Preoperative assessment of lymphatic vessels is critical in LVA surgery, and is one major reason for the need for imaging in these patients. Specifically, it is essential that one confirm the presence of at least one functional subcutaneous lymphatic vessel that can transport lymphatic fluid, since an anastomosis to that subcutaneous lymphatic vessel will be performed. Ideally, this determination should be made in the clinic prior to going to the operating room. In some cases, all of a patient’s subcutaneous lymphatic vessels may have been scarred as a result of progressive lymphedema, making LVA surgery impossible. This can occur, for example, in patients with longstanding lymphedema. While in some instances the absence of any suitable subcutaneous lymphatic vessels for bypass will correlate with the extent of lymphedema as assessed by physical examination, this is not always the case[22]. The subcutaneous veins involved in LVA surgery do not require any specific imaging as they are numerous and generally unaffected by the pathologic processes that affect subcutaneous lymphatic vessels.
Modelling uptake and transport of therapeutic agents through the lymphatic system
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
T. D. Jayathungage Don, V. Suresh, J. E. Cater, R. J. Clarke
Consequently, computational models can play an important role in quantifying lymphatic drainage. In this regard, however, the lymphatic system has received much less attention than its cardiovascular counterpart. Many of the existing models focus on a specific feature of the lymphatic vessel physiology. For example, Reddy and Patel (Reddy and Patel 1995) developed a two-dimensional mechanical model of a lymphatic capillary pore, and considered the opening mechanism which occurs when anchoring filaments are placed under tension by the surrounding tissue. Mendoza and Schmid-Schönbein (2003) have also considered the capillary pore mechanics, treating them as junctions that can open by bending under an applied loading. This was later extended by others through the addition of the interstitium, and consideration of the junction’s nonlinear mechanics (Galie and Spilker 2009).
Related Knowledge Centers
- Adventitia
- Extracellular Fluid
- Lymph
- Smooth Muscle
- Endothelium
- Lymphatic System
- Capillary
- Circulatory System
- Blood Vessel
- Lymph Capillary