血液稍微稠密，粘稠度约为水的3-4倍。血液由悬浮在液体中的细胞组成。与其他悬浮液一样，血液成分可以通过过滤分离，然而，最常用的分离血液的方法是离心（旋转）它。在离心血液中可见三层。稻草色的液体部分，称为等离子体，在顶部形成（~55％）。在等离子体下方形成薄的奶油色层，称为血沉棕黄层。血沉棕黄层由白血细胞和血小板组成。红细胞形成分离混合物的重底部分（约45％）。血容量是可变的，但往往约为体重的8％。身体大小，脂肪组织量和电解质浓度等因素都会影响体积。一般成年人约有5升血。血液由细胞物质（99％的红细胞，白细胞和血小板构成其余部分），水，氨基酸，蛋白质，碳水化合物，脂类，激素，维生素，电解质，溶解气体和细胞废物组成。每个红细胞按体积计约为1/3血红蛋白。血浆约为92％的水，血浆蛋白质是最丰富的溶质。主要的血浆蛋白质组是白蛋白，球蛋白和纤维蛋白原。主要的血气是氧气，二氧化碳和氮气。
澳洲墨尔本大学医学Essay代写：什么是血液的体积和化学成分？
Blood is slightly more dense and approximately 3-4 times more viscous than water. Blood consists of cells which are suspended in a liquid. As with other suspensions, the components of blood can be separated by filtration, however, the most common method of separating blood is to centrifuge (spin) it. Three layers are visible in centrifuged blood. The straw-colored liquid portion, called plasma, forms at the top (~55%). A thin cream-colored layer, called the buffy coat, forms below the plasma. The buffy coat consists of white blood cells and platelets. The red blood cells form the heavy bottom portion of the separated mixture (~45%). Blood volume is variable but tends to be about 8% of body weight. Factors such as body size, the amount of adipose tissue, and electrolyte concentrations all affect volume. The average adult has about 5 liters of blood. Blood consist of cellular material (99% red blood cells, with white blood cells and platelets making up the remainder), water, amino acids, proteins, carbohydrates, lipids, hormones, vitamins, electrolytes, dissolved gasses, and cellular wastes. Each red blood cell is about 1/3 hemoglobin, by volume. Plasma is about 92% water, with plasma proteins as the most abundant solutes. The main plasma protein groups are albumins, globulins, and fibrinogens. The primary blood gasses are oxygen, carbon dioxide, and nitrogen.