There the function of each of the three

There are three different types of blood cells circulating through the bloodstream. Learn about the function of each of the three types of blood cells, and test your knowledge by taking the quiz.

Introduction to Blood Cells

Our blood is often referred to as the river of life running through our bodies, but why is this analogy used? Part of the reason for this comparison can be found by exploring the different types of blood cells that flow through this river.

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There are three main types of blood cells found in the body. These are the erythrocytes, leukocytes and thrombocytes. Let’s look at each of these a little closer.

Red Blood Cells

The first type of blood cells are the erythrocytes, or as they are commonly called, red blood cells. These are the most numerous of the three types of blood cells, and they’re unique in that they contain no nucleus.

Red blood cells function as a transportation system. Think about what happens with a bus. The bus begins a route and picks people up. As the bus continues along the route, people will get off and others will get on at different stops. Eventually, the bus returns to where it started, but not with the same people on the bus.

The red blood cells work in a similar way.Red blood cells pick up oxygen from the lungs and start on a route to the different organs in the body where the oxygen needs to go. After the oxygen is used by the organs, carbon dioxide is produced as a waste product.

The red blood cells pick up the carbon dioxide from the organs in the body and take it to the lungs for it to be removed from the body.

White Blood Cells

The next type of blood cell are the leukocytes, also known as white blood cells. These blood cells also have a very important role in the body. They function to protect the body from anything that could harm the body. You can think of the white blood cells as the police officers of the body.

The police officers, or white blood cells, patrol the body looking for pathogens, or bad guys, that could harm the body. Just like there are different kinds of police officers, such as patrol officers, detectives, etc., there are different types of white blood cells.The first type of white blood cell is the lymphocyte. The lymphocytes are further divided into T cells and B cells. Both lymphocytes work together to help your body produce immunity to the different pathogens that have invaded the body.

The T cells present the pathogens to the B cells, and then the B cells produce an antibody that can destroy the pathogen. The B cells will remember the antibody that was created for each pathogen, so that it can make the antibody again if the pathogen comes into the body again.The next type of white blood cell is the monocyte. Monocytes function by phagocytosing, or engulfing the pathogens that come into the body. They can then break the pathogen down into smaller pieces and present the pathogen to the T cells to start the immunity process that we just discussed. The monocytes are unique because of their ability to also leave the blood to go into the organs of the body and protect the organs by eating any pathogens, or anything else, that doesn’t belong in the organs.

The last type of white blood cell is the granulocyte. The granulocytes get their name due to having granules on their surface. There are 3 different types of granulocytes. The first ones are the neutrophils. These are the most numerous of the white blood cells and are active early on when a pathogen causes an infection in the body. Neutrophils seek out and destroy bacteria and fungi that are invading the body.

Their action in an infection is actually was causes the white pus that is seen at the site of infection. Next are the eosinophils that are responsible for targeting and fighting off parasites that invade the body. The last of the granulocytes are the basophils. These are the ones that many people probably wish didn’t exist, since they are ones that cause us to have allergic reactions. When basophils come into contact with an allergen, they release a chemical known as histamine which causes the blood vessels in the body to get larger, giving the red, inflamed look when we have an allergic reaction.


The last of the three blood cell types are the thrombocytes, commonly referred to as platelets.

These are also the tiniest of the blood cells. Platelets work in the body to help stop the bleeding whenever a blood vessel is damaged. When a cut occurs in a blood vessel, a signal is sent that causes the platelets to come to the damaged part of the blood vessel. The platelets stretch out, pile on top of each other and stick together to form a plug to stop the bleeding from the blood vessel.

This begins the repair process.

Lesson Summary

We now know the different types of blood cells and their functions. The erythrocytes, or red blood cells, are our transport system for the oxygen that the body needs and the carbon dioxide that the body doesn’t need.Our defenders are our white blood cells that protect our body from the many germs that are around us every day and make their way into our bodies. The different types of leukocytes, also know as white blood cells, are the neutrophils that fight off bacterial and fungal infections, basophils that release histamine and cause allergic reactions, eosinophils that fight against parasitic infections, monocytes that phagocytize pathogens and present them to T cells, B cells that create antibodies against pathogens and T cells that present the pathogen to the B cells.

Both B cells and Tcells are called lymphocytes.The platelets, or thrombocytes, are the ones that keep us from bleeding to death when we get cut and start the repair process. So, our blood cells give us the oxygen we need, protect us from infection and keep our blood in the proper place. It’s no wonder the blood is referred to as the river of life.


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