Pulmonary lymphatics

The pulmonary lymphatic system contributes to the clearance of fluid and protein from the lung tissue interstitium and helps to prevent fluid accumulation in the lungs [108], The lymphatic endothelium allows micron-sized particles (e.g. lipoproteins, plasma proteins, bacteria and immune cells) to pass freely into the lymph fluid [103], After administration of aerosolised ultrafine particles into rats, particles were found in the alveolar walls and in pulmonary lymph nodes [135], which suggests that drainage into the lymph may contribute to the air-to-blood transport of the inhaled particles. 

Many dissolved proteins that have been transported through the alveolar cells are rapidly reabsorbed into the blood through the capillary endothelial cells (also by transcytosis). In the case of some large proteins, they are more slowly drained across the interstitial space by means of the pulmonary lymphatics, which also empty into the bloodstream via the thoracic duct and superior vena cava. 

The pulmonary region includes the functional gas exchange sites of the lung. The terminal bronchioles of the TB tree branch to form the respiratory bronchioles. The major structural elements of the parenchyma of this region of the lung include the alveolar ducts, alveolar sacs, alveolar capillaries, and pulmonary lymphatics. The walls of the tubular alveolar ducts are covered with alveoli. As these branch, they... 

Edema Caused by Lymphatic Dysfunction. Pulmonary lymphatic insufficiency resulting from lymphatic carcinoma, silicosis, anesthesia, or sedative drug overdose can cause a decreased clearance of fluid from the lung via the lymphatics. Because of the absence of this important mechanism for fluid removal from the lung, lymphatic insufiiciency can rapidly lead to an accumulation of fluid in the lung interstitium and ultimately to pulmonary edema. 

Pulmonary lymphatics are critical to clearing dust particles which have reached the lung fluid. 

Using scanning electron microscopy of casts by a resin cast into the pulmonary blood vasculature of oedematous lungs, Schraufnagel (1992) categorised four forms of pulmonary lymphatics ... 

From studies in spontaneous hypertensive rats, Aharinejad et al. (1999) suggested that pulmonary lymphatic filling is associated with pulmonary venous sphincters, and perivascular muscle action might be a component of the pulmonary lymphatic system. 

Landrigan PJ, Cherniack MG, Lewis FA et al (1986) Silicosis in a grey iron foundry. The persistence of an ancient disease. Scand J Work Environ Health 12 32-39 Lauweryns JM, Baert JH (1977) Alveolar clearance and the role of pulmonary lymphatics. Am Rev Respir Dis 115 625-683... 

Lauweryns JM, Baert JH. Alveolar clearance and the role of the pulmonary lymphatics. Am Rev Respir Dis 1977 115 625-683. 

Virtually all particles that deposit in the alveoli, and some portion of particles that deposit in the conducting airways, are phagocytosed by macrophages and either transported proximally along the airways, or transported through the pulmonary lymphatics to lymph nodes. But neither mucociliary clearance nor alveolar macrophages form a perfect defense (78), and even in the absence of overload (see following discussion) some, apparently quite small, fraction of deposited paticles is taken up by alveolar or airway epithelial cells, as can be deduced from Tables 1 and 2. 

Pulmonary arteriole Elastic connective tissue Lymphatic... 

Hi-receptors mainly mediate the constriction of large and relaxation of small blood vessels, contractions of the bronchial, intestinal and uterine smooth muscle and contractions of vascular endothelial cells with the result of an increased capillary permeability. The lymphatic flow is augmented by Hi-receptor stimulation. H2-receptor stimulation induce a dilatation of pulmonary arteries, a positive inotropic and chronotropic effect on the heart and an increased glandular secretion, especially in the mucosa of the stomach. 

Postmortem examinations of persons who died as a result of exposure to H have shown depletion of lymphoid cells in the spleen, thymus, and other lymphatic organs depletion of hematopoietic cells of the bone marrow necrosis and desquamation of epithelium in the small intestine acute ulceration of the duodenum membranous laryn-gotracheobronchitls and pulmonary edema, congestion, and patchy emphysema that may be complicated by bronchopneumonia or other evidence of pulmonary infection.2>47... 

N.A. Aescin, citric acid, resin, saponin, tannin, uric acid, quercetin, kaempferol, flavonoids, coumarin derivatives.99,100 Antipyretic, antithrombin, antiexudative. Treat lymphatic congestions, cerebral and pulmonary edema, crural ulcer and hemorrhoidal complaints. 

Dermal or intravenous exposure to lewisite leads to local skin edema and pulmonary edema due to increased capillary permeability. The increased capillary permeability results in blood plasma loss and resultant physiological responses collectively referred to as lewisite shock . Lewisite shock may be likened to shock observed in severe bum cases. It has been hypothesized that functional changes in the lungs, kidneys, respiratory tract, cardiovascular, and lymphatic systems may be the result of a disturbance of osmotic equilibrium (Goldman and Dacre, 1989). 

FIGURE 31.2. Spore uptake in inhalational anthrax disease. The steps involving spore deposition into a pulmonary alveolus, margination of alveolar macrophages out of capillaries into the alveolar space, spore uptake, and entry into lymphatic channels are illustrated. Illustrations are copyright protected and printed with permission by Alexandre M. Katos. 

Fig. 1 Inhaled drug in a carrier can exist in the slow clearing pulmonary compartment (Pi) without mucociliary clearance or in the faster clearing pulmonary compartment with mucociliary clearance (P2), tracheobronchial compartment (TB) or gastrointestinal tract (GI). When the drug is released into these compartment (the released drug is represented by italicized letters Pi, P2, TB, GI), it can be absorbed into the bloodstream, or it can be removed by non-productive pathways such as mucociliary clearance represented by the vertical arrows, or chemical and enzymatic decomposition. Large molecules may also enter lymphatics before they appear in the blood stream. (The detailed model was described while the simplified three-compartment model represented by the ellipses is from Refl l)...

No oral MRLs were derived for metallic (elemental) mercury due to the lack of data. Oral exposure to liquid metallic mercury would be expected to present little health risk, since it is so poorly absorbed (<0.01%) through the healthy intestine. Sufficiently large quantities could, however, present a risk of intestinal blockage, and some could enter the systemic circulation (blood or lymphatic) through open lesions, presenting a risk of occlusion of smaller arteries, especially within the pulmonary circulation. 

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