Functions of Blood 


blood-definition-functions-and-its-components-3-638Blood is a connective tissue that makes up almost 8 per cent of a person’s body weight. It is in a fluid form due to the plasma, which is a thick liquid that transports nutrients, gases and other substances. The other components of blood include three types of blood cells- platelets, red blood cells and white blood cells. Each part has its own functions that are essential for you to survive.


The average temperature of blood in your body is 38 °C and the amount of blood in your body depends on your gender and weight. This essential liquid in our body has the following main functions:


This is the primary function of this connective tissue. Blood takes the oxygen from the lungs and transports it to the cells. It then takes the carbon dioxide produced by the cells and transports it to the lungs, which you then exhale. This fluid also transports hormones, removes any waste material as well transports nutrients to cells. It also promotes body temperature by transporting heat to your skin.


The components of blood help protect your body from diseases and infections. While the antibodies get rid of harmful substances, the white blood cells are known to destroy cancer cells as well as any harmful microorganism. The platelets, on the other hand, come in handy when you get injured, as it helps prevent blood loss, by clotting.


Blood regulates the pH balance of your body by keeping a check on the concentration of the Hydrogen ions. It also maintains the water balance in your body by transporting the right amount of water to and from your tissues. This fluid also maintains your blood pressure at the normal level.


There are four major components of blood as stated above, plasma, white blood cells, red blood cells and platelets.


The main component of blood is the plasma, which makes up 55% of the total fluid. Plasma is not red in color, but is of a yellowish, pale color. This is because it is around 90 per cent water and the rest is dissolved substances like proteins.

The functions of plasma include transporting glucose to the cells so that they can convert it into energy. Plasma also transports triglycerides, cholesterol, vitamins, fatty acids and amino acids.

Cortisol and thyroxin hormones also attach themselves to the plasma proteins and are then transported to the cells. These plasma proteins keep the pH balance of the body intact by doing away with any excess hydrogen ions in the blood.

Plasma is also beneficial in preventing loss of blood by promoting the blood vessels to clot. The antibodies gammaglobulins in the plasma also help prevent disease and infections.

White Blood Cells

White blood cells are that part of the blood fluid that helps fight bacteria, viruses, germs etc. There are different types of white blood cells and each one has its own functions. Some fight bacteria and infections and get rid of them, while others attack any foreign bodies like parasites and germs. download (4)

There are some that also make you aware of dust particles and other harmful substance in order to stop you from inhaling these into your body.  For instance, these components make you sneeze when you come in contact with dust particles, so that they don’t enter the body.

There are other parts which fight any cancer cells produced in the body. These white blood cells can survive from a few hours to several years and they have no hemoglobin content.

Red Blood Cells

This hemoglobin content is present in the other component of blood, the red blood cells. This hemoglobin is what transports energy and so it is the red blood cells that take the oxygen from the lungs to the cells. It also takes out the carbon dioxide from the cells to the lungs to exhale.

These blood cells can also transport and release hydrogen and nitrogen. When they release or pick up hydrogen, they help maintain the pH balance. When they release nitrogen, they help lower blood pressure by making the blood vessels expand.

These red blood cells use the veins and arteries to travel in the body and the wall of the veins is smaller as compared to arteries. This is because the blood pressure is not very high when passing through the veins. But it is extremely high when passing through the arteries and hence it needs to have a thicker wall.

These red blood cells normally last for around 120 days and when they are damaged or old these cells are broken into pieces in the liver or bone marrow.


Blood platelets are the smallest and lightest component of the blood fluid. They are mainly responsible for clotting the blood when there is an injury or wound. What happens is that on a normal basis, blood platelets do not stick to the walls of the blood vessels because of special cells in the vessels.

But when you get injured these special cells of the blood cells are destroyed and the blood starts flowing out of these vessels. This is when the platelets come in handy. The platelets get attached to the blood vessel wall and combine together to form a blood clot that stops the blood from flowing out.

This is why you must always ensure that your platelet count is at the normal level. If you have a low blood platelet level, your blood will not clot during an injury and thus you would lose a lot of blood.

Thus these components work together to keep your body intact and healthy. Blood helps transport oxygen and carbon dioxide to and from the cells, fights antibodies, kills cancer cells and prevents loss of blood.