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Pulmonary (lung) circulation undergoes hypoxic vasoconstriction, which is a unique mechanism of local regulation in that the blood vessels in this organ react to hypoxemia, or low levels of dissolved oxygen in blood, in the opposite way as the rest of the body. While tissues and organs tend to increase blood flow by vasodilating in response to ...
Regulation of renal blood flow is important to maintaining a stable glomerular filtration rate (GFR) despite changes in systemic blood pressure (within about 80-180 mmHg). In a mechanism called tubuloglomerular feedback , the kidney changes its own blood flow in response to changes in sodium concentration.
Substances called vasoconstrictors can reduce the size of blood vessels, thereby increasing blood pressure. Vasodilators (such as nitroglycerin) increase the size of blood vessels, thereby decreasing arterial pressure. If the blood viscosity increases (gets thicker), the result is an increase in arterial pressure.
The narrowing of blood vessels leads to an increase in peripheral resistance, thereby elevating blood pressure. While vasoconstriction is a normal and essential regulatory mechanism for maintaining blood pressure and redistributing blood flow during various physiological processes, its dysregulation can contribute to pathological conditions.
Hypocapnia (from the Greek words ὑπό meaning below normal and καπνός kapnós meaning smoke), also known as hypocarbia, sometimes incorrectly called acapnia, is a state of reduced carbon dioxide in the blood. [1] Hypocapnia usually results from deep or rapid breathing, known as hyperventilation. Hypocapnia is the opposite of hypercapnia.
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 ...
When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance and increase in cardiac output [further explanation needed]. Vascular resistance is the amount of force circulating blood must overcome in order to allow perfusion of body tissues. Narrow vessels create more vascular resistance, while dilated ...
This is as the nitric oxide decreases the pulmonary circulation's resistance by dilating pulmonary blood vessels. The increased pulmonary return increases pressure in the left atrium, causing closure of the foramen ovale and reducing the blood flow through the ductus arteriosus.