Blood is considered the fluid connective tissue of the human body. Blood consists of plasma and blood cells. Plasma is the liquid component, and different types of blood cells are suspended in it.
RBC, WBC, and Platelets are the different types of blood cells. Each blood cell has a peculiar function.
- Red blood cells (RBCs) are the cellular components of blood that transport oxygen, while hemoglobin is the iron-containing protein within RBCs responsible for oxygen binding.
- RBCs are biconcave in shape to increase surface area for oxygen exchange, while hemoglobin has a quaternary structure that enables efficient binding and release of oxygen.
- Anemia can result from a low RBC count or hemoglobin levels, impacting the body’s oxygen-carrying capacity.
RBC vs Hemoglobin
Red blood cells are the most common type of blood cell and are responsible for carrying oxygen from the lungs to the body’s tissues and removing carbon dioxide from the body. Haemoglobin is a protein found inside red blood cells that helps transport oxygen and carbon dioxide throughout the body.
RBC is also known as Red blood corpuscles or erythrocytes. They are the common type of blood cell in vertebrates. Their main function is to supply oxygen to all the body cells.
The oxygen molecules entering the lungs through respiration are taken up by the RBCs and transported to different body parts through circulation.
Haemoglobin is a protein in red blood cells. It helps the RBC in carrying oxygen and carbon dioxide. Haemoglobin is a metalloprotein. It has Iron and globin.
It gives RBC and blood their red color. Haemoglobin is a red-colored pigment. There are many other pigments, like haemoglobin, that are present in some invertebrates.
|Parameters of Comparison
|Consists of four subunits with four polypeptide chains each attached to one heme group.
|RBC is present in the blood
|Hemoglobin is present in the RBC
|4.7-6.1 million cells per microliter for men and 4.2-5.4 million per microliter for women
|14-18 g per deciliter for men and 12-15 grams per deciliter for women.
|Red pigment protein
|Transports hemoglobin bound to respiratory gases and supply oxygen to the body tissues
|Binding to respiratory gases
|Releases free radicals and lyse pathogen
|Functions as antioxidant and regulate iron metabolism
What is RBC?
Red blood corpuscles are enucleated oval or biconcave disk-shaped structures. They are formed and matured in the bone marrow. Their lifespan is 100-120 days.
They lack a nucleus as they make space to accommodate the red pigment haemoglobin. 2.4 million new RBCs are produced every second in humans.
They make up 40-45% of the total volume of blood.
The cell membrane of RBC is permeable to oxygen molecules. Oxygen enters RBC through diffusion. It then travels in the blood to different body parts and enters the cells.
Human RBC has a diameter of 6.2-8.2µm. Women have 4-5 million RBC per microliter of blood, while men have 5-6 million RBC per microliter of blood.
Their major function is to transport oxygen. During stressful conditions, RBCs release ATP, which leads to the relaxation of blood vessels, eventually leading to normal blood flow.
They also have some immunological functions. When attacked by a pathogen, they release free radicals to lyse the pathogen’s cell wall and kill it.
Having a normal RBC count is healthy. An increase or decrease in the number of RBCs may cause certain diseases. A decrease in the number of RBCs leads to a condition called Anemia.
Anaemia may be caused by Vitamin B12 or folate deficiency, stomach ulcer, or excessive blood loss. An increase in the number of RBCs causes Polycythemia.
What is Hemoglobin?
Haemoglobin is the protein pigment present in RBC. It is made up of four amino acid chains. A heme group is attached to each of these chains.
The heme group is made up of a porphyrin ring and an iron atom. Each haemoglobin molecule can carry four oxygen atoms.
The iron atoms temporarily bind with the oxygen atoms. This binding is temporary, and oxygen dissociates and enters the cells upon reaching the target cells.
Haemoglobin also carries back a small amount of carbon dioxide, the waste product of cellular respiration.
Haemoglobin also causes changes in blood color. When haemoglobin combines with oxygen forming Oxyhemoglobin, the blood is scarlet or bright red.
Deoxyhemoglobin is formed when oxygen is released, giving the blood a dark burgundy color. Haemoglobin also combines with carbon monoxide forming carboxyhemoglobin.
Haemoglobin is responsible for the transportation of 98% of the total oxygen in humans.
The haemoglobin content of a healthy individual is 12-14 g per 100 ml of blood. Haemoglobin makes up 96% of the total weight of RBC.
Haemoglobin is also present in other body parts like macrophages, alveolar cells, lungs, hepatocytes, retinal pigment, etc. and functions as an antioxidant and iron metabolism regulator.
Main Differences Between RBC and Hemoglobin
- RBCs are blood cells involved in oxygen transportation. In contrast, haemoglobin is the pigment present in RBC which binds with oxygen and is responsible for oxygen transportation by RBC.
- RBC is biconcave, disc-shaped, enucleated blood cells produced in the bone marrow. In contrast, haemoglobin is a metalloprotein made up of globin and heme.
- An increase in RBC causes Polycythemia, while an increase in haemoglobin causes hemoglobinemia.
- A decrease in RBC causes a condition called anaemia, characterized by fatigue and pale skin. A decrease in haemoglobin leads to thalassemia, engagement of the spleen, vasculitis, and anaemia by lowering the RBC’s ability to carry oxygen.
- The main function of haemoglobin is to bind with respiratory gases and hold them. But, RBC has a major function of transporting the gases bound to haemoglobin to different parts of the body through blood.
Last Updated : 14 June, 2023
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.