美国移植外科医生协会关于正常热区域输液的共识声明

Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The velocity of blood flow decreases with increased cross-sectional blood vessel area. As blood returns to the heart through venules and veins, its velocity increases. The movement of blood is encouraged by smooth muscle in the vessel walls, the movement of skeletal muscle surrounding the vessels, and one-way valves that prevent backflow.

Veins, while chiefly responsible for circulating blood back to the heart, also function as storage vessels for blood. They house approximately 64 percent of the body's total blood volume, a feat made possible by their high capacitance—the inherent ability to expand and accommodate large volumes of blood, even under low pressure. The large diameter and thin walls of veins augment their distensibility, significantly more so than arteries, due to their classification as capacitance vessels. When...

Tissue transplantation is a significant medical procedure involving the transfer of cells, tissues, or organs from a donor to a recipient, with the primary aim of restoring lost functions. This procedure is crucial in treating a broad spectrum of diseases, including kidney diseases, liver failure, heart disease, and certain types of cancers.
The Biology of Tissue Transplantation
The biology of tissue transplantation hinges on the Major Histocompatibility Complex (MHC) molecules. These molecules...

Varicose veins, or varicosities, develop when the valves in the veins, which control blood flow, weaken or damage. It causes blood to pool and the veins to enlarge. Understanding the clinical manifestations, diagnostic approaches, and management options for varicose veins is crucial for effective treatment and relief.Clinical manifestationsClinical manifestations of varicose veins include a heavy, achy feeling or pain after prolonged standing or sitting. This discomfort can often be relieved by...