And while that metaphor may not give pause to your average English professor, it does score points for accuracy. Blood, after all, is as much about movement and transport as it is platelets and plasma. That's the science, but there's more. It's also very dynamic. It's continuously growing and dying.
Whole blood is comprised of cellular and fluid components.
The fluid is called plasma and contains nutrients, proteins and other blocks. Red blood cells contain hemoglobin, a complex protein that carries oxygen throughout the body, giving blood its red color. According to the AABB, there are about one billion red cells in every two to three drops of blood. Red cells are manufactured in bone marrow and live for approximately 120 days in the circulatory system. Broken down cells are removed by the spleen.