Why Is Blood Red In Color?

Why Is Blood Red In Color?

The first lesson a child learns from science class about blood is that it is red in color. However, many fail to understand the appearance of blue/green veins on the skin despite the red color of the blood.

Since the answer to the question regarding the color of the veins is not that easy to explain, some adults simply tell their children false facts. In reality, it is actually y really simple to explain stuff like this as well as clear many other misconceptions about blood.

What Are Some Common Misconceptions About Blood? 

What Is The Color Of Blood? 

You may often hear that deoxygenated blood is blue. But all blood inside human body has one color that is red. The primary component of blood is called hemoglobin. It is a protein molecule found in red blood cells.

The hemoglobin contains iron, which reacts with oxygen, giving blood its red color. It may give your veins appear blue which is obvious from the skin. But the color of blood is never blue but red. The reason why veins seem blue is due to the level of oxygen in the blood.

The arteries in the body are responsible for transport blood. The arteries draw this oxygen-rich blood away from the heart to the visceral organs. This blood comes back to the heart in deoxygenated form from the body.

Many people will tell you that veins are blue because they carry deoxygenated blood. The blood of humans is red regardless of how much oxygen is present in it. But the shade of red in the blood may vary from person to person.

The amount of oxygen makes these hues of the red inside of it. When the blood leaves the heart it has the highest amount of oxygen at this stage, that’s why it appears bright red. When this blood comes back to the heart, it has comparatively less oxygen in it. It may still be red but not bright. It is dark red at this point.

Which Species Has Blue Blood?

Animals, like humans, have red blood. Though all humans have red blood, not all animals have red blood. There are a few exceptions where animals have blue blood. For example, some types of octopus, squids, and crustaceans have blue blood in their body.

This blue blood containing animals have a high concentration of copper in them. This copper mixes with oxygen and the process gives their blood blue shade instead of red.

Interestingly, blue and red are only two possible options for blood and no one has a third color of blood. Rarely some animals bleed green.

The skink, a type of lizard has a different colored blood. It is green due to the buildup of biliverdin in blood. This Biliverdin and bilirubin are by-products of the life in animals. Humans produce these two by-products as well.

The human body sends these two compounds to the excretory system via the digestive system. But skinks do not excrete them. That is why it builds in the body and changes the color of their blood.

What Is the Amount of Blood Present In the Human Body?

Blood is an essential part of the human body. Can you guess how much blood is present inside your body? There is no as such an exact amount of blood in the body. It varies from person to person. Usually, a huge person has more blood volume.

From the total weight of a person, only 7% to 8% is the weight of blood. It means the average sized woman has 9 pints and man has 12 pints in them.

How Much Is Accidental Blood Loss Safe?

Losing too much blood accidentally makes you enter in a life-threatening condition called hemorrhagic shock. It is evident by research that this shock only occurs when a person loses 20% or more than their actual blood volume.

The obvious symptoms of hemorrhagic shock include dizziness, low blood pressure, and confusion. Your doctor will treat this hemorrhagic shock with fluid resuscitation and blood transfusions.

RELATED: Is Your Potassium Deficiency Causing High Blood Pressure? 

How Many Blood Types Are There? 

There are certain types of blood. Although the blood looks and seems the same to everyone in real this is not 100% the same in all individuals. There are vital elements that are present in everyone’s blood.

In human blood, there are red blood cells, white blood cells, platelets and plasma cells. Everyone has all of these components of blood yet their blood has different types.

These types of blood are based on the presence or absence of specific antigens and antibodies on the surface of the red blood cells. You can understand antigen, which initiates an immune response in the body.

Talking about the most common antigens, there are two of them. One is A and the other B. People that have blood type A will have A-antigen on their red blood cells, and those people who have type B blood have a B-antigen. Only some people have both of them.

People that have an O blood group have no A or B antigens in them. This blood group O is the most common blood type worldwide. The second type of antigen is a protein called the Rhesus (Rh) factor.

Why Is Blood Red In Color?

Those people which have this protein are called Rh-positive and those without it are called Rh-negative. The Rh-positive blood is more common to have Rh-positive blood than Rh-negative.

When a person who is Rh-negative wanted a transfusion, needs blood, he is never given Rh-positive blood. This blood type depends upon ethnic and racial trends as well.

For example, blood group B is very common for Asians and those with Asian descents. Type A and B are the most common antigens. Other antigens are less common.

How Do Blood Transfusions Work? 

Blood transfusion is a process to donate blood. Blood transfusion is healthy when it is medically processed. The reasons why people go for blood transfusions are;

  • Severe blood loss due to accident, surgery
  • Blood loss due to childbirth
  • Anemia in which person doesn’t have enough RBCs
  • Cancer and cancer treatments i.e. chemotherapy
  • Any disease that affects sickle cell disease

If a person in is need of a blood transfusion, it is necessary to give them a compatible blood type. Injecting them with a wrong type of blood will make their lives endangered.

Most of the people receive O blood type while blood transfusion, regardless of their blood type. That is why the O blood group is the most desirable of donation clinics.

Is Blood Donation Safe? 

It is healthy to donate blood. It saves lives and also makes you feel good about yourself. When the blood is excessively lost, it may put your life in danger.

If you are willing to donate blood, make sure to follow the complete medical protocol for it. In addition, make sure to check the blood before you receive it in a transfusion.

Why Is Blood Red In Color?

Things To Keep In Mind 

Blood is an essential part of the human body. It is required for performing a majority of the functions. It has various myths attached to it. However, not all of them are true. It is better to have accurate information about blood and anything related to blood transfusion.

If you are not sure about a health issue, it is better to talk to your doctor about it. you can also do this personal search to know the basic information.


Andrea White

As a graduate of Public Health and Policy, Andrea developed an interest in disease development, food and safety and the latest advancements in health. She is a Freelance writer who had affiliations with multiple blogs. Andrea is now pursuing her post-doctorate in Behavioral Sciences.

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