Why are arteries blue?

Question

I thought:
a) arteries carry oxygenated, therefore red, blood
b) the blood vessles seen near the surface of the skin (inside of the elbow, for instance) are arteries
So why do these vessels appear blueish? Are they actually veins?

Answer 1

Usually, surface vessles are venous flow, not arterial. Arteries are high pressure lines, and need substantial protecion, therefore arteries run deep, not on the surface.
So, YES, they are indeed veins, not arteries.

Answer 2

Neither Arteries nor Veins are blue.

If you would like to look at some blood vessels that you can see, sometime, have a good close look at the whites of someones eyes. You can see the blood vessels below the transparent coverings of the eye there quite well.

They are RED! (In fact, the arteries themselves if emptied of blood are quite white.)

The blood in your body is red.

The blood in your veins is red - even before it touches the outside air.

What makes the veins in your arms/wrists APPEAR to be blue is the fact that there are several layers of skin over the top of it. Those are the veins, by the way, not the arteries.

(a) is correct. Arteries carry oxygenated blood. This is red. Please please PLEASE understand that the blood in veins is also red - much darker coloured, but red nevertheless. Ask any medical doctor you like. Ask the phlebotomists - the blood technicians. They can tell you.

(b) is incorrect. The blood vessels seen near the surface of the skin (inside the elbow, for instance) are veins. Your arteries are hidden a little deeper - all the better to protect them from sharp pointy things. You can find your arteries by feeling around your elbow or your wrist. The arteries pulsate. The veins do not (well - if you used a pressure transducer in them, they do pulsate a little - but it is not easily detectable with your fingers).

Answer 3

This is a common misconception. The distinction of arteries vs. veins is not whether or not the blood is oxygenated or deoxygenated but instead which direction blood is going from the heart.

Arteries always carry blood away from the heart. In the case of systemic arteries like the aorta, femoral artery or brachial artery, all carry bright red oxygenated blood. In the case of the pulmonary artery (from the heart to the lungs), they carry dark red purplish deoxygenated blood. So there are "blue" arteries as well as "red" arteries.

Veins carry blood back to the heart. For systemic veins, the the vena cavas or the median cubital vein on the anterior part of your elbow, all carry dark red purpleish deoxygenated blood. In fact all vessels you see at the surface are systemic veins. For your pulmonary veins (from lung to heart), these carry bright red oxygenated blood. So veins can also be "blue" or "red".

So a question you might ask, why if you scrap an elbow the blood is red and not darker red purpleish. Well the instant you the blood is exposed to the air, it grabs oxygen and as a result turns red.

Answer 4

The large blood vessels nearer to the skin surface are usually veins, while arteries, which run in antiparallel circuits, are situated deeper in the tissues. There are also deep veins that run alongside the arteries.
Veins carry deoxygenated blood, which is darker and blueish (actually, more violet than blue) than oxygenated blood, and they also tend to have larger diameter and thinner walls than arteries, that's why they're so visible. Their relatively thin walls are also the reason that varices develop in veins.

Those large vessels inside of your elbow are veins (the basilic, median cubital, and cephalic veins); arteries are not as easy to pierce with a needle when you give a blood sample.
Check here, there's a diagram of the veins in the hand and arm:
http://www.nehb.ie/nehb/services/guidelines/guidelinea.doc

Answer 5

I thought the big ones were arteries and the small ones veins. Maybe the color of the vessel has nothing to do with the color of the blood inside? Guess i shouldn't have cut class so much in medical school

Answer 6

neither veins nor arteries are actually blue, it is the oxygenated blood that turns blue as the lungs introduce oxygen into the blood

Answer 7

Yes, they are veins. No artery is that visible through skin.
Have you ever seen a heart?

Answer 8

blood is blue when it does not have oxygen in it, its read when it does have oxygen in it. So blue arteries and veins are carying blood back to your heart and lungs, the blood has given its oxygen to your body's cells and is returning to your lungs for more oxygen.

Answer 9

oh confident very everyday, you additionally can get stretch marks on your boobs besides as they'll probably strengthen besides. the stretch marks I even have their are like a purplish colour, u can get stretch marks everywhere on your physique once you're pregnant, you additionally can get those blue veins particularly lots everywhere besides. its very everyday.

Answer 10

because blood is blue until it is exposed to air which turns it red! arteries and veins are clear.