How Much Blood is in the Human Body

Everybody is familiar with the red-colored liquid, called blood, that flows throughout the human body. This bodily liquid carries out many important functions in the body, like transporting nutrients and oxygen to the body cells. It also takes away the wastes from the cells. It is responsible for carrying hormones and chemicals to various parts of the body. Blood plays an important role in keeping the body temperature steady by transporting excess heat from some areas to the skin, where it is dissipated. It is an important part of the immune system and one of the characteristics of blood is its disease fighting ability. In case of a wound, the platelets in blood can coagulate and stop the bleeding. It is considered as the body's self-repair mechanism, which prevents further blood loss, that can be fatal for the human body systems.

Components of Blood

Human blood consists of an yellowish fluid called plasma, in which the blood cells are suspended. Blood cells form around 45% of the blood and the remaining 55% is plasma. Almost 90% of plasma is water, which contains dissolved glucose, proteins, hormones, mineral ions, platelets and blood cells. The blood cells include red blood cells (RBCs or erythrocytes) and white blood cells (WBCs or leucocytes). Other than these two, there are platelets, which are also known as thrombocytes. The most abundant among them are the RBCs, which can number roughly five million in a cubic millimeter of human blood. The same amount of blood contains about 5,000 to 10,000 WBCs and 200,000 to 300,000 platelets. RBCs contain hemoglobin, which imparts the red color to blood, when oxygenated. A deficiency of hemoglobin can lead to a disease called anemia.

How Much Blood is in the Human Body?

Most people are aware of the importance of blood, yet many are ignorant of how much blood is in the human body. The total amount of blood in the human body can vary with several factors, like age, sex, health condition, body type, etc. But as far as an average adult (with a body weight between 150 to 180 pounds) is concerned, the volume of blood can be between 4.7 to 5.5 liters. In case of a child with a body weight of 80 pounds, the volume of blood can be around half the amount of that of an adult and it will be around eight ounces in an eight pound infant. It is also believed that as compared to males, the volume of blood in women is slightly less. These figures do not apply to people living in high altitudes, as they have a comparatively higher volume of blood in their bodies. When compared to those living in low altitude regions, people in high altitudes may have around two liters of extra blood. As high altitudes have a low amount of oxygen in the air, the people in that region need extra blood to deliver oxygen to their lungs.

According to some studies, the volume of blood in a human body is 7% of the body weight. The density of the blood in a normal person is around 1060 kg/m3, which is almost close to the density of pure water, i.e. 1000 kg/m3. Hope this article would have enlightened you on how much blood is in the human body and how important is its role in maintaining the health of humans.