What is the color of blood Why it red outside?

Color of Blood: Inside vs Outside the Body

The color of blood is determined by the presence of hemoglobin, an iron-containing protein inside red blood cells responsible for carrying oxygen throughout the body. Hemoglobin appears bright red when it carries oxygen (oxygenated hemoglobin) and darker red or bluish-red when it releases oxygen (deoxygenated hemoglobin).

Why Blood Appears Red Outside the Body

When blood is exposed to air outside the body, it turns bright red. This is because oxygen in the air reacts with the hemoglobin in the blood, converting it into oxygenated hemoglobin, which has a bright red color.

Factors Influencing Blood Color

1. Oxygenation: The oxygen saturation level of hemoglobin significantly impacts blood color. When blood is fully oxygenated, it appears bright red, while deoxygenated blood has a darker red or bluish-red color.

2. Lighting Conditions: The ambient light can affect how blood appears. Under natural daylight or bright artificial light, blood typically appears red, but in low light or certain artificial lighting conditions, it may appear darker or brownish.

3. Concentration of Red Blood Cells: The number of red blood cells (RBC count) in the blood can also influence its color. A higher RBC count leads to a darker red color, while a lower RBC count can make the blood appear paler or pinker.

4. Medical Conditions: Certain medical conditions, such as anemia (low RBC count), carbon monoxide poisoning (impairs oxygen transport by hemoglobin), and methemoglobinemia (abnormal hemoglobin that can't carry oxygen), can alter the color of blood.

It's important to note that the color of blood alone does not provide a conclusive medical diagnosis. If you have concerns about the appearance or color of your blood, it's always best to consult with a healthcare professional.