Organ alterations due to aging

Aging defined as progressive organ dysfunction which makes keeping homeostasis more difficult starts at the age of 30–40. However, due to difficulties with the distinction between aging and disease processes, changes previously believed to be caused by aging are often recognized as the effect of pathologies when new data is presented. According to current knowledge, cardio-vascular aging includes decreased elasticity of main arteries, decreased ability of left ventricule to relaxate, diminished function of sino-atrial node and decreased effect of beta-adrenergic stimulation. Aging in the respiratory system is attributed to increased size of alveoli and alveolar ducts (which easier collapse), a decrease in the gase exchange area, a decrease in respiratory volumes (both static and dynamic) and a severe decrease in maximal oxygen consumption. In aging kidneys both renal blood flow and glomerular filtration are decreased. As the result of tubular alterations the kidney ability to conserve and dilute urine, and its capability to regulate the pH and serum sodium level diminish. Less dramatic changes are seen in the gastrointestinal tract. According to available data, high prevalence of gastric atrophy and hypochlorhydria are a consequence of Helicobacter pylori infection. Also, constipation is attributed much more to sedative life style and diet than to aging itself. In summary, none of the presented alterations is severe enough to cause the disease, but all of them increase the risk of pathology and thus pave the way for the disease even in healthy elderly subjects.