Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

Difference Between RBC and WBC

share icon
share icon
banner

Introduction

Both red blood cells and white blood cells play an essential role in the human body. Red blood cells or RBC carry oxygen to the tissues in different parts of the body. White blood cells or WBC strengthen the defense mechanism of the body by generating antibodies. The primary difference between RBC and WBC lies in their functionality. While RBCs act as carriers, WBC act as creators. The experts at Vedantu have summarized the difference between red blood cells and white blood cells in a comprehensive manner.


Red Blood Cells (RBC)

As the name suggests, RBC is red because of the presence of hemoglobin which is an iron-rich protein and binds with oxygen to get the red color. RBC gives a red color to the blood because of its presence in the blood in a large number. Also known as Erythrocytes, red blood cells are round, small, and bi-concaved in shape but due to their flexibility, they appear bell-shaped when passing through small vessels. They carry oxygen to the tissue in the body. To maintain a healthy RBC count in the body, it is essential to take an iron and vitamin-rich diet. A low RBC count causes anemia and its common symptoms are irregular heartbeat, pale skin, feeling cold, fatigue, and joint pain.


(Image will be uploaded soon)


The primary function of Red Blood Cells is to carry oxygen from the lungs to the tissue in different parts of the body, using the blood circulation system. They also carry carbon dioxide back to the lungs from where they are excreted out of the body. Since the RBC has a bi-concave shape it helps in the exchange of oxygen at a constant rate and over a large surface area.


White Blood Cells (WBC)

White Blood Cells are colorless due to the absence of hemoglobin in them. Also known as Leukocytes, white blood cells protect the body from any infections by producing antibodies that build up the defense system of the body against germs and infections. One of the other important factors that help us to differentiate between RBC and WBC is the circulation system used by these cells. WBC uses cardiovascular circulation and is also present in the lymphatic system. Red blood cells use only the cardiovascular circulatory system. Invading bacteria, viruses, and germs are attacked by these cells, which aid in the fight against infection.


(Image will b uploaded soon)


Although white blood cells begin in the bone marrow, they circulate throughout the body. There are five different types of white blood cells:

  • Neutrophils

  • Lymphocytes

  • Eosinophils

  • Monocytes

  • Basophils


The primary function of white blood cells is to produce antibodies in the body and to strengthen immunity of the body. A good defense mechanism protects the body from any germ attacks or infections. WBC protects the body by digesting the foreign material and cancer cells present in the body by producing antibodies.


Let’s look at the difference between red blood cells and white blood cells in detail.


Difference Between Red Blood Cells and White Blood Cells

Criteria

RBC

WBC

Scientific name 

RBC is scientifically called Erythrocytes.

WBC is called Leukocytes.

Appearance

RBCs are anucleated, bi-concave, and disc-shaped.

WBC are nucleated and irregular in shape.

Size

The size of RBC is roughly 6-8 microns.

The size of WBC is 15 microns.

Production location

RBC is produced in the red bone marrow.

WBC is produced in the spleen, lymph nodes, etc.

Production number

Almost 2 million RBC are produced in the body per second.

WBC are produced in a comparatively lower number than the RBC.

Formation process 

The process of RBC formation is called Erythropoiesis.

The process of WBC formation in the body is called leucopoiesis.

Motility

Red Blood Cells are non-motile.

White blood cells are motile

Percentage in blood

RBC accounts for 36%-50% of the blood in the body. This percentage, however, differs according to the height, weight, and age of the person.

In comparison, WBC constitutes a meager 1% of the blood.

Types

Red blood cells are only of one type.

White blood cells are of multiple types. T-lymphocytes, B-lymphocytes (plasma cells), monocytes (macrophages), neutrophils, eosinophils, and basophils are some of the types of WBC.

Life span

RBC can survive up to 120 days in the body.

WBC can survive anywhere between several days to even several years in the body.

Constitution

RBC is made up of only hemoglobin.

WBC is made up of antibodies with MHC antigen cell markers.

Colour 

The presence of hemoglobin lends a red color to the RBC. It is the reason they are called red blood cells.

The absence of hemoglobin makes WBC colorless.


Function

The primary function of the RBC is to carry oxygen to the various parts of the body. As a secondary function, they also carry waste materials and carbon dioxide to the lungs.

The primary function of WBC is to produce antibodies to strengthen the defense mechanism of the body. These antibodies protect the body from any attack by germs and provide immunity against infections. Some of them are also phagocytic.

Circulation

The circulation system used is the cardiovascular system that is related to the blood vessels and the heart.

The circulation systems used are cardiovascular as well as lymphatic. 

Low count effect

A low RBC count in the body can lead to anemia which can affect the body’s ability to carry and supply oxygen to the tissues.

A low WBC count can lead to leukopenia that can hamper the immune system of the body.

High count effect

A high RBC count is produced in the body during exercise or at high altitudes.

A high WBC count is an indication of infection present in the body or of a lower response rate of the bone marrow. Such a condition is called Leukocytosis.

Want to read offline? download full PDF here
Download full PDF
Is this page helpful?
like-imagedislike-image

FAQs on Difference Between RBC and WBC

1. What are the main differences between Red Blood Cells (RBCs) and White Blood Cells (WBCs)?

Red Blood Cells (RBCs) and White Blood Cells (WBCs) are key components of blood, but they differ significantly in their structure, function, and characteristics. Here are the primary differences:

  • Function: RBCs are responsible for transporting oxygen from the lungs to the body's tissues, while WBCs are the primary agents of the immune system, defending the body against infections and diseases.
  • Colour: RBCs contain haemoglobin, an iron-rich protein that binds to oxygen and gives them their characteristic red colour. WBCs lack pigments and are therefore colourless.
  • Nucleus: Mature RBCs are anucleated (lack a nucleus) to maximise space for haemoglobin. In contrast, all WBCs possess a distinct, often multi-lobed, nucleus.
  • Shape: RBCs have a unique biconcave disc shape, which increases the surface area for gas exchange. WBCs have an irregular or amoeboid shape, allowing them to squeeze through blood vessel walls to reach sites of infection.
  • Count: RBCs are far more numerous, with a count of about 4.5 to 5.5 million cells per microlitre of blood. The WBC count is much lower, typically ranging from 4,000 to 11,000 cells per microlitre.
  • Lifespan: RBCs have a longer lifespan of about 120 days, whereas the lifespan of WBCs is much shorter, varying from a few hours to several days depending on the type.

2. What is the primary function of Red Blood Cells (RBCs)?

The primary function of Red Blood Cells, also known as erythrocytes, is to transport oxygen from the lungs to all the cells and tissues throughout the body. They achieve this using an iron-containing protein called haemoglobin, which binds with oxygen. RBCs also play a role in transporting carbon dioxide, a waste product, back to the lungs to be exhaled.

3. What is the primary function of White Blood Cells (WBCs)?

The primary function of White Blood Cells, or leukocytes, is to protect the body against infectious diseases and foreign invaders. They are a crucial part of the immune system. Different types of WBCs perform specific roles, such as engulfing pathogens (phagocytosis), producing antibodies to neutralise threats, and regulating the immune response.

4. Why do Red Blood Cells lack a nucleus while White Blood Cells have one?

This structural difference is directly related to their functions. Mature Red Blood Cells lack a nucleus to maximise intracellular space for haemoglobin, thereby increasing their oxygen-carrying capacity. This anucleated state also gives them the flexibility to squeeze through narrow capillaries. White Blood Cells, however, retain their nucleus because it contains the genetic information necessary to synthesise proteins, produce antibodies, and direct their complex immune functions like identifying and destroying pathogens.

5. How do platelets differ from both RBCs and WBCs?

Platelets, or thrombocytes, differ from both RBCs and WBCs in structure and primary function. Unlike RBCs and WBCs, platelets are not true cells but are small, irregular cell fragments originating from large bone marrow cells called megakaryocytes. Their main function is blood clotting (haemostasis). When a blood vessel is damaged, platelets aggregate at the site to form a plug, initiating the clotting cascade to prevent excessive bleeding. This is distinct from oxygen transport (RBCs) and immunity (WBCs).

6. What are the health implications of having an abnormal count of RBCs or WBCs?

An abnormal count of either RBCs or WBCs can indicate underlying health issues. A low RBC count or insufficient haemoglobin leads to anaemia, causing symptoms like fatigue, weakness, and shortness of breath. A low WBC count (leukopenia) weakens the immune system, making a person highly susceptible to infections. Conversely, a high WBC count (leukocytosis) often signals an ongoing infection, inflammation, or in severe cases, a condition like leukemia, which is a cancer of the blood-forming tissues.

7. Why is the biconcave shape of an RBC so important for its function?

The biconcave disc shape of an RBC is crucial for its function for two main reasons. Firstly, it significantly increases the surface-area-to-volume ratio, which facilitates a faster and more efficient diffusion of oxygen and carbon dioxide across the cell membrane. Secondly, this shape provides remarkable flexibility, allowing the RBC to deform and pass through extremely narrow capillaries, some of which are narrower than the diameter of the cell itself, ensuring oxygen reaches every part of the body.