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The astronomical seeing conditions at an observatory can be conveniently described by the parameters r 0 and t 0. For telescopes with diameters smaller than r 0, the resolution of long-exposure images is determined primarily by diffraction and the size of the Airy pattern and thus is inversely proportional to the telescope diameter.
In healthy lungs where the alveolar dead space is small, Fowler's method accurately measures the anatomic dead space using a single breath nitrogen washout technique. [ 4 ] [ 5 ] The normal value for dead space volume (in mL) is approximately the lean mass of the body (in pounds), and averages about a third of the resting tidal volume (450-500 mL).
Gas is breathed at ambient pressure, and some of this gas dissolves into the blood and other fluids. Inert gas continues to be taken up until the gas dissolved in the tissues is in a state of equilibrium with the gas in the lungs (see saturation diving), or the ambient pressure is reduced until the inert gases dissolved in the tissues are at a higher concentration than the equilibrium state ...
Air in the alveoli of the lungs is diluted by saturated water vapour (H 2 O) and carbon dioxide (CO 2), a metabolic product given off by the blood, and contains less oxygen (O 2) than atmospheric air as some of it is taken up by the blood for metabolic use. The resulting partial pressure of nitrogen is about 0.758 bar.
The bronchial circulation is the part of the systemic circulation that supplies nutrients and oxygen to the cells that constitute the lungs, as well as carrying waste products away from them. It is complementary to the pulmonary circulation that brings deoxygenated blood to the lungs and carries oxygenated blood away from them in order to ...
By redirecting blood flow from poorly-ventilated lung regions to well-ventilated lung regions, HPV is thought to be the primary mechanism underlying ventilation/perfusion matching. [ 1 ] [ 2 ] The process might initially seem counterintuitive, as low oxygen levels might theoretically stimulate increased blood flow to the lungs to increase gas ...
The process of breathing does not fill the alveoli with atmospheric air during each inhalation (about 350 ml per breath), but the inhaled air is carefully diluted and thoroughly mixed with a large volume of gas (about 2.5 liters in adult humans) known as the functional residual capacity which remains in the lungs after each exhalation, and ...
In the vacuum of space, gas exchange in the lungs continues but results in the removal of all gases, including oxygen, from the bloodstream. After 9 to 12 seconds, the deoxygenated blood reaches the brain, and it results in the loss of consciousness. [26] Exposure to vacuum for up to 30 seconds is unlikely to cause permanent physical damage. [27]