If our blood is blue before it meets oxygen, then why is the blood red in the syringe?

It is a common misconception that veinous blood (without oxygen) is blue, and arterial blood (oxygen enriched) is red. Veinous blood is only slightly bluish, when compared with arterial blood, and is still bright red (slightly brick red). When we look at the veins in our wrist, they seem blue; but we are looking at the vein itself; not the blood within it. Also, it is not as blue as it seems. Try this simple test: Place a blue pencil alongside the vein. Compared to the blue of the pencil, the vein will then seem red. It only looks blue, compared to the skin of your wrist. When you see the blood in the syringe, you see its true colour.

who said our blood is blue? looking at this question brought back to mind that when i was a small child, i looked at my lower arms, just above my hands and saw the veins. they were blue and asked my mom about our blood being blue. she smiled and set me straight once and for all. of this info? i shall pass it onto you. our blood is red, always was red and remains red no matter what! it has a strong copper base and you can smell it when drawn or dried. this is why blood turns brownish in color. now, why are my veins in parts of my body showing blue, you ask? it's the veins themselves and not what passes through them. the walls of the veins are lined with capillaries that show a blueish color and when stressed, such as varicose veins, often look dark almost black. this is normal and not to be confused with the wonderful fluid that without, we'd be without!

Blood is not blue...the sheath of the veins is blue. That's why our veins look blue from the outside.

you need to study some biology dude

Firstly, blood is not blue, it is only slightly bluish when de-oxygenated. When oxygenated, the oxygen has combined with haemoglobin forming oxy-haemoglobin, which is reddish.

Your blood is only blue if you are an octopus, because they have a copper based molecule carrying oxygen. Humans have an iron-based molecule - hemoglobin - and that gives our red cells their red color. The shade of red depends on the oxygen content of the blood. It can be a very dark red, almost black, when there is no oxygen (dead or almost dead person) and bright red when fully oxygenated.

blood is never blue

I think I know where you are coming from. Blood is bright red when it is carrying oxygen yes, but its oxygen it picks up from the lungs. When it delivers its oxygen to the cells throughout the body, it sheds the oxygen and picks up CO2 and other waste products - that is where it picks up the darker red/bluish apperance that gives veins thier blue appearance. Its the oxygen poor blood you are seeing in the veins in your skin. Once that blood reaches the lungs again, it turns bright red again, you just don't see that because the arteries that travel away from the heart are deeper down thier your veins, which are near the surface.