About 90% of the straw-colored plasma are water in which a number of substances are dissolved. Those substances include proteins, hormones, nutrients like glucose, vitamins, amino acids, lipids, gases like carbon dioxide, oxygen, salts like sodium, calcium, potassium, magnesium, and wastes such as urea. Plasma proteins are the most abundant of the dissolved substances.
The three major plasma proteins are albumins, which help maintain the blood's osmotic pressure, which controls the flow of water across cell; globulins, which transport nutrients and also play a role in the immune system; and fibrinogen, important in blood clotting.