Blood

Blood is a specialized fluid connective tissue that contains cells suspended in a fluid matrix. From this explanation, we can conclude that blood contains two kind of substances, solid and liquid.

The liquid substance of blood is called plasma. 92% of plasma is water. Proteins such as albumins, globulins, fibrinogen, etc. only fulfill 7% of plasma. The rest 1% are other solutes like electrolytes and organic substances.

In outline, the solid substances of blood are divided in three types. Red blood cells, white blood cells, and platelets. Each of it has its own function.

Red blood cells or erythrocytes are the biggest part of formed elements of blood. That’s why, the color of blood is red. These specialized cells are essential for the transport of oxygen in the blood. It can carry oxygen because it has hemoglobin (Hb), that responsible for the cell’s ability to transport oxygen and carbon dioxide.

White blood cells, also called leukocytes, participate in the body defense mechanisms. There are five classes of leukocytes, each with different functions.

Platelets are small, membrane-bound cell fragments that contains enzymes and other substances important to the process of clotting.

Blood is a vehicle. It transports nutrients, hormones, dissolved gases, and metabolic wastes to the part of the body that lacked of it. As the blood flows, it also stabilize the body temperature and remove debris or fight infections.

Although the contains of blood aren’t different from one person to another, we can’t transfer someone’s blood to other inaccurately. If their blood isn’t the same type, there can be a dangerous agglutination in recipient’s body. It can kill recipient, the one who receive the blood. So, human’s blood is classified.

There are four blood types. A, B, AB, and O. Sometimes ago, there are epithet like universal donor and universal recipient. Universal donor refer to O type. It means, people with O blood type can give their blood to other people with different blood type. Universal recipient means the other way. It refer to AB type.

But for now, it didn’t valid anymore. Because, there are chances to agglutination if we transfer someone’s blood to another that isn’t in the same type even it from the universal donor or to the universal recipient. And still, it’s dangerous.