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On the other hand, gravity causes a gradient in blood pressure between the top and bottom of the lung of 20 mmHg in the erect position (roughly half of that in the supine position). Overall, mean pulmonary venous pressure is ~5 mmHg. Local venous pressure falls to -5 at the apexes and rises to +15 mmHg at the bases, again for the erect lung.
Transmural pressure is the difference in pressure between two sides of a wall or equivalent separator. According to myogenic theory smooth muscle contract in response to increased transmural pressure and relax to decreased transmural pressure For body vasculature or other hollow organs, see Smooth muscle#External substances
Critical closing pressure is the internal pressure at which a blood vessel collapses and closes completely. [1] When blood pressure falls below critical closing pressure, the vessel is unable to overcome external pressure (either from environment or vascular smooth muscle) and flow stops.
The pulmonary arteries carry deoxygenated blood to the lungs, where carbon dioxide is released and oxygen is picked up during respiration. [3] Arteries are further divided into very fine capillaries which are extremely thin-walled. [4] The pulmonary veins return oxygenated blood to the left atrium of the heart. [3]
People who are affected by a PSP are often unaware of the potential danger and may wait several days before seeking medical attention. [15] PSPs more commonly occur during changes in atmospheric pressure, explaining to some extent why episodes of pneumothorax may happen in clusters. [13] It is rare for a PSP to cause a tension pneumothorax. [12]
These blockages cause increased resistance to flow in the pulmonary arterial tree which in turn leads to rise in pressure in these arteries (pulmonary hypertension). The blockages either result from organised (or hardened) blood clots that usually originate from the deep veins of the lower limbs of the body ( thromboembolism ) and lodge in the ...
cardiac causes, pulmonary causes and; non-pulmonary and non-cardiac causes. Considered physiologically, pulsus paradoxus is caused by: [citation needed] decreased right heart functional reserve, e.g. myocardial infarction and tamponade, right ventricular inflow or outflow obstruction, e.g. superior vena cava obstruction and pulmonary embolism, and
The increase in pulse pressure may result in increased damage to blood vessels in target organs such as the brain or kidneys. [23] [24] This effect may be exaggerated if the increase in arterial stiffness results in reduced wave reflection and more propagation of the pulsatile pressure into the microcirculation. [23]