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Veins have less smooth muscle and connective tissue and wider internal diameters than arteries. Because of their thinner walls and wider lumens they are able to expand and hold more blood. This greater capacity gives them the term of capacitance vessels. At any time, nearly 70% of the total volume of blood in the human body is in the veins. [3]
Such situations include, but are not limited to, the need for long-term venous access (for weeks or months, not days), [1] administering of medications that can damage smaller veins (e.g. chemotherapy), measuring central venous pressure, obtaining certain blood tests (specifically central venous oxygen saturation), or performing dialysis.
Oxygen-poor blood enters the right side of the heart through two large veins. Oxygen-rich blood from the lungs enters through the pulmonary veins on the left side of the heart into the aorta and then reaches the rest of the body. The capillaries are responsible for allowing the blood to receive oxygen through tiny air sacs in the lungs.
Typical values for the viscosity of normal human plasma at 37 °C is 1.4 mN·s/m 2. [3] The viscosity of normal plasma varies with temperature in the same way as does that of its solvent water [ 4 ] ;a 3°C change in temperature in the physiological range (36.5°C to 39.5°C)reduces plasma viscosity by about 10%.
Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein.The intravenous route of administration is commonly used for rehydration or to provide nutrients for those who cannot, or will not—due to reduced mental states or otherwise—consume food or water by mouth.
In medicine, venipuncture or venepuncture is the process of obtaining intravenous access for the purpose of venous blood sampling (also called phlebotomy) or intravenous therapy. In healthcare, this procedure is performed by medical laboratory scientists , medical practitioners , some EMTs , paramedics , phlebotomists , dialysis technicians ...
Distension of the vessels due to increased blood pressure is a fundamental stimulus for muscle contraction in arteriolar walls. As a consequence, microcirculation blood flow remains constant despite changes in systemic blood pressure. This mechanism is present in all tissues and organs of the human body.
The peripheral vascular system is the part of the circulatory system that consists of the veins and arteries not in the chest or abdomen (i.e. in the arms, hands, legs and feet). [1] [2] The peripheral arteries supply oxygenated blood to the body, and the peripheral veins lead deoxygenated blood from the capillaries in the extremities back to ...