anatomical basis of pleural effusion

Pleural effusions associated with pulmonary diseases or malignancy emphasise the absorptive efficiency of the pleura. This review focuses attention on the major role of the lymphatic drainage system in absorbing fluids from the pleural cavity. Mesothelial cells of the diaphragmatic pleura in particular overlie a rich plexus of lymphatic lacunae strategically located within the submesothelial connective tissue. The existence of patent stomata between mesothelial cells of the diaphragm ensures continuity between the pleural cavity and the lymphatic lacunae. These pleurolymphatic stomata are exclusive to the diaphragm and may serve as the main drainage channels for absorption of particulates, pathogens and tumour cells from the pleural cavity. Pleural effusion may develop when production of pleural fluids exceeds the capacity of the lymphatic system and when inflammation or malignant infiltration involves any component of this drainage system

effect of stress on the immune system

It has been known for many years that mental attributes influence resistance to some diseases. The recently bereaved students preparing for examinations and individuals who are mentally depressed, all show reduced lymphocyte reactivity. The brain, especially the hypothalamus, controls neurotransmitter function of the autonomic nervous system. This influences immune reactivity through ACTH secretion by the pituitary which is regulated by feedback mechanisms of adrenal hormones levels. Consequently, primary and secondary lymphoid organs are affected. Stress can depress T-cell mitogenesis, natural killer [NK] cell activity and interleukin-2 [IL2] production. Cells react to stressful stimuli by synthesising and accumulating a specific group of stress proteins'. They are involved in assembling, disassembling and translocation of certain protein complexes through intracellular membranes. They can also interact with steroid hormone receptors, viral and cellular kinases, actin and tubulin. They have been implicated as being essential for viral replication and assembly of a variety of bacterial viruses. Stress-related thymic atrophy may be responsible for decreased cellular immunity. Profound uncontained stress may indeed cause body systems, including the immune system, to suffer with an increased vulnerability to disease