By volume, blood tissue is approximately 55% plasma and 45% cells. plasma is a straw-colored liquid consisting of 90% water and a variety of salts and proteins important for maintaining osmotic balanc

By volume, blood tissue is approximately 55% plasma and 45% cells. plasma is a straw-colored liquid consisting of 90% water and a variety of salts and proteins important for maintaining osmotic balance, buffering against ph changes, maintaining blood viscosity, transporting certain materials, and for blood clotting when a blood vessel is injured.