The lymphatic system

Lymph means (Clear fluid), and it is a “Proteinaceous fluid” that contain more white blood cells than plasma. The lymph is similar in composition to the extracellular fluid, but it contains large amount of proteins (40-60 gL-1), of which albumin is the main part (23-34 gL-1). This thick fluid is moved and pumped by the muscles surrounding it (Like when you squeeze toothpaste); accumulation of lymphatic wastes in the body causes “Gaining weight” that do NOT respond to diet or slimming regimes

Lymphatic vessels are found in all over the body, even in the central nervous system. Lymphatic drainage of the gut and solid organs (e.g., liver, pancreas, stomach … etc.) is through the “Cisterna chyli”, which is located at the level of L1 vertebra

The movements of the lymph toward the head upward are passive and slow (1-2 ml/sec), and are under the influence of 2 main pumps: (1) the diaphragm movement; and (2) Muscle contraction. At rest, the lymph volume at the level of the thoracic duct is (2-3 liter / day)

The lymphatic system is the body’s “Sewage” system, and it has two major branches:

a. Superficial system: it flows below the skin, and constitute up to 60-70% of the lymphatic flow in the body. This system depends on “Deep breathing” as its main moving engine

b. Deep system: it flows adjacent to the veins, forming larger vessels until it empty in the citerna chyli

Cells dump their waste products into the extra-cellular fluid. Most of these wastes are carried into the venous system, except “Proteins”, because of their large size, are carried by the lymphatic system. Many toxins in the extracellular fluid space are NOT water-soluble (Hydrophobic); therefore, they are transported via the lymphatic system. Because the lymphatic system carries fat-soluble wastes, macromolecules (e.g. proteins), and microbes, it is filled with lymphocytes and immune cells that work as “Disinfectants”, cleaning these microbes

The major components of the lymphatic system are:

1. Lymphatic vessels: arising near the capillaries at the extracellular fluid space level. These vessels have valves like the veins, and they carry the lymph (fat-soluble extracellular fluid waste) into bigger vessels (e.g., cisterna chili; located in front of L2 vertebra), that end into 2 main system: (1) The right thoracic duct (Drain the right upper body and right arm; 1.5 cm long); and (2) the left thoracic duct (Drain the rest of the body; 38-45 cm long). Both thoracic ducts empty into the subclavian veins into the systemic circulation. The large lymphatic vessels reach as much as 25 mmHg

2. Lymph nodes: are small glands scattered in body regions, mainly in flexor surfaces. These glands serve 2 main functions: (1) Eliminate bacteria from the lymph; and (2) Cloning of T-lymphocytes. The lymphatic node cortex is densely-packed with lymphocytes (T-cell mainly), while the lymphatic node medulla is densely-packed with macrophages and plasma cells 

3. Lymphatic tissues: these are scattered lymphatic tissues found in different body tissues, and include: Waldeyer’s tonsillar ring (an oropharyngeal lymphoid tissue that include adenoids, palatine tonsils, and lingual tonsils), MALT (Mucosal-Associated Lymphoid Tissue), NALT (Nose-Associated Lymphoid Tissue), VALT (Vulvovaginal-Associated Lymphoid Tissue), SALT (Skin- Associated Lymphoid Tissue), BALT (Bronchial-Associated Lymphoid Tissue), GALT (Gut- Associated Lymphoid Tissue – Peyer’s patches), and the Appendix (Intestinal tonsil)

4. Spleen: is a “Blood filter”, working by eliminating the impurities and toxins poured from the lymph into the blood. Also, it has secondary lymphoid tissues that produce lymphocytes, monocytes, and antibodies


Selected references

1. Greene AK et al. Lymphedema: presentation, diagnosis, and treatment. 2015; Springer-Verlag; 1st edition

2. Lee BB et al. Lymphedema: a concise compendium of theory and practice. 2011; Springer-Verlag; 1st edition

3. Ossipinsky J. An undetected acid-alkaline imbalance. 2006; Vision Publishing, LLC; 1st edition