Search results
What color is blood? There’s no need to build up the suspense: Blood is red. It might vary from a bright cherry red to a dark brick red, but it’s always red.
- Overview
- 1. What color is blood?
- 2. Do some animals have blue blood?
- 3. How much blood is in the body?
- 4. How much blood can a person safely lose?
- 5. What are blood types?
- 6. What are blood transfusions?
- 7. How important is blood donation?
- Takeaway
- GeneratedCaptionsTabForHeroSec
All blood in the human body is red in color. It is untrue that deoxygenated blood is blue.
In this article, we look at a variety of facts about blood, including color, types, and donation.
Human blood contains hemoglobin, which is a complex protein molecule in red blood cells.
Hemoglobin contains iron. The iron reacts with oxygen, giving blood its red color.
Although veins appear blue through the skin, blood is not blue. The reason why veins might seem to be blue may have to do with the level of oxygen in the blood.
Arteries transport blood that is rich in oxygen away from the heart to be used by organs and tissues in the body. The veins return deoxygenated blood to the heart.
It is a common myth that veins are blue because they carry deoxygenated blood. Blood in the human body is red regardless of how oxygen-rich it is, but the shade of red may vary.
The level or amount of oxygen in the blood determines the hue of red. As blood leaves the heart and is oxygen-rich, it is bright red.
Similar to people, most animals also have red blood. However, there are a few exceptions.
Some types of octopus, squid, and crustaceans have blue blood. Their blood contains a high concentration of copper. When copper mixes with oxygen, it gives their blood its blue color.
Blue and red are not the only possible colors of blood — some animals bleed green.
The skink, which is a type of lizard, has green blood due to a buildup of biliverdin. Biliverdin and bilirubin are by-products of the liver. Humans also produce these two by-products.
Everyone knows that blood is a vital component of the human body. But just how much blood is in the body? The exact amount of blood in the body varies according to a person’s size. The larger a person is, the more blood volume they have.
Approximately 7–8 percent of a person’s total weight is blood. That means an average-sized woman has about 9 pints of blood and an average-sized man about 12 pints.
If a person loses too much blood, it can lead to a life-threatening condition called hemorrhagic shock.
Research shows that shock usually occurs when a person loses 20 percent of their blood volume.
Everyone’s blood contains the same elements or components. Human blood contains red cells, white cells, platelets, and plasma. Even though all blood contains those same components, not everyone’s blood is alike.
There are different blood types based on the absence or presence of specific antigens and antibodies on the surface of the red blood cells. An antigen is a substance that can cause an immune system response in the body.
The two most common antigens are A and B. For example, people with the blood type A have an A-antigen on their red blood cells, and people with type B blood have a B-antigen. Some people have both.
People with O blood type do not have either A or B antigens on the red blood cells. Type O is the most common blood type in the world.
Another antigen is a protein called the Rhesus (Rh) factor. People with this protein are considered Rh-positive. If the blood lacks the protein, they are Rh-negative.
It is more common to have Rh-positive blood than Rh-negative. If a person who is Rh-negative needs a transfusion, they should not receive Rh-positive blood.
Blood transfusions are when healthy blood from a donor is injected into a person who needs it.
Common reasons to have a blood transfusion include:
•Severe blood loss from surgery, an accident, or childbirth.
•Anemia, when a person does not have enough red blood cells.
•Some types of cancer and cancer treatment, including chemotherapy.
•Conditions that affect the red blood cells, such as sickle cell disease.
Without a blood transfusion, significant blood loss or severe anemia can be life-threatening.
Donating blood can save lives. For those who are unsure about donating blood, it is helpful to consider the facts below:
•Around 5 million people in the United States receive blood each year.
•The Red Cross estimates that someone needs blood about every 2 seconds.
•Although research is underway to make synthetic blood, currently blood for transfusions only comes from donors.
•Typically, a person will donate just 1 pint of blood at a time.
Blood is essential for the functioning of the human body, but many myths about the body persist. Having accurate information about blood or any other aspect of health is vital.
If someone is in doubt about a health issue, it is essential to talk to a doctor to get the most accurate information.
Blood is not blue, but it may appear blue in veins due to the level of oxygen. Learn about blood types, blood volume, blood donation, and more.
The most common blood color in humans and animals is red. Hemoglobin is present in humans, most other vertebrates, and some invertebrates as well. Pigment Structure. A hemoglobin molecule is a complex structure made of four globular polypeptide chains that are joined together, as shown in the illustration above.
Hemoglobin is the principal determinant of the color of blood (hemochrome). Each molecule has four heme groups, and their interaction with various molecules alters the exact color. Arterial blood and capillary blood are bright red, as oxygen imparts a strong red color to the heme group.
Learn about the vital functions of blood, its fluid and cellular components, and its physical characteristics. Explore the structure and function of red blood cells, hemoglobin, white blood cells, and platelets, as well as blood disorders and transfusions.
Feb 20, 2024 · What Color Is Blood? Blood in humans is red. It may be a dark red or a bright red, depending on the amount of oxygen present, but human blood is not blue. Blood with lots of oxygen appears a bright red color, whereas venous blood with less oxygen appears a darker, deeper red color.
Oct 28, 2014 · The differing structure of the pigment, as well as the incorporation of copper atoms instead of iron, leads to the blood being colourless when deoxygenated, and blue when oxygenated. They also bind to oxygen in a different manner to haemoglobin, with two copper atoms binding to each oxygen molecule.
