Your blood is red, so why are your veins blue?Fernando MarinhoDavid Anderson
Below is a selection from a popular science book.If blood is red, why are veins(静脉)blue?Actually, veins are not blue at all. They are more of a clear, yellowish colour. Although blood looks redwhen it's outside the body, when it's sitting in a vein near the surface of the skin...
The three major types of blood vessels are arteries, veins, and capillaries. Arteries are the large, muscular vessels that carry oxygenated blood away from the heart into the tissues. Capillaries are tiny blood vessels that are the site of gas and nutrient exchange between the blood and the su...
(标题1)If blood is red,why are veins(静脉)blue?Actually,veins are not blue at all.They are more of a clear,yellowish color.Although blood looks red when it’s outside the body,when it’s sitting in a vein near the surface of the skin,it’s more of a dark reddish purple color....
Veins carry deoxygenated blood towards your heart and are often located close to your skin. Veins don’t have a muscular layer like arteries do, so they rely on valves to keep your blood moving. Veins start as tiny blood vessels called venules, which become full-size veins as they come ...
C. Veins D. Capillaries Blood Vessels: Generally speaking, blood vessels can be categorized according to whether they carry blood to or away from the heart. The oxygen content in blood will vary depending on whether blood is being sent to or away from t...
The smallest blood vessels are the a. arteries. b. veins. c. lymphatics. d. capillaries. The Mammalian Circulation: The circulation in mammals consists of a closed system of blood vessels, the arteries, capillaries and veins and a pump organ called heart. Through ...
Veins are elastic blood vessels that transport blood from various regions of the body to the heart. Veins are components of the cardiovascular system, which circulates blood to provide nutrients to the cells of the body. Unlike the high pressure arterial system, the venous system is a low pres...
题目【题目】The heart is believed to __blood in to veins(血管) which are netted all over the bo dy, thus keeping a person alive. A. give B. donate C. circulateD.pump 相关知识点: 试题来源: 人教版高中英语必修五unit1-2基础知识点训练题 解析 【解析】D ...
Induced depletion of intimal macrophages leads to thrombin-mediated endothelial cell contraction, progressive fibrin accumulation and formation of microthrombi that, once dislodged, cause blockade of vessels in several organs. Together the findings reveal that intravascular resident macrophages are essential ...