Pulmonary artery and pulmonary vein?
 

Dear friends! Please solve my following confusion:

Artery is a blood vessel that carries oxygenated blood from heart to all parts of the human body while vein brings de-oxygenated blood from the body cells to the human heart. The function of both is clearly defined. Now the question is [B]why Pulmonary Artery carries de-oxygenated blood from the heart to the lungs and a pulmonary vein brings oxygenated from the lungs to the heart?[/B]
Why both vessels have different functions here or why both have twisted names here?

Knowledgeable members are requested to explain it.

Thanks and regards

Arteries are vessels that take blood away from the heart and veins are vessels that carry blood to the heart. The pulmonary artery carries deoxygenated blood away from the heart to the lungs and the pulmonary vein returns oxygenated blood to the heart from the lungs. Generally, arteries carry oxygenated blood and veins carry deoxygenated blood but that is now how they're defined. The vessels are defined as those that take blood away from the heart and those that return blood to the heart. I could go in deeper if you want. Hope it helps.

[QUOTE=azeegum;402230]
Arteries, [COLOR="Blue"]except the pulmonary artery[/COLOR], carry oxygenated blood from heart to all parts of the human body while veins, [COLOR="blue"]exception being the pulmonary vein[/COLOR], bring de-oxygenated blood from the body cells to the human heart.
[/QUOTE]

The pulmonary artery and the pulmonary vein are just exceptions to the definition.

They're not exceptions to the definition, they're divided into vessels that carry blood to the heart and those that carry blood away from the heart.
Dr. Asad Shafiq

Can anybody tell me why do veins look green (or blue) while the blood is red?

Deoxygenated blood is generally a dusky or darker red colour. Veins appearing green or blue has more to do with the type of light waves reflected off the skin, thus appearing as green or blue. It varies from skin tone to skin tone.

[QUOTE=Hamidullah Gul;402269]Can anybody tell me why do veins look green (or blue) while the blood is red?[/QUOTE]

The color of blood looks green or blue because we're viewing it through a layer of vein wall, skin and hypodermis(subcutaneous tissue). Those tissues bend the light, like the atmosphere bends the light in the sky, turning it blue.

Further, any Doctor will better explain it. ;)

[QUOTE=Asad Shafiq;402255]They're not exceptions to the definition, they're divided into vessels that carry blood to the heart and those that carry blood away from the heart.
Dr. Asad Shafiq[/QUOTE]

Couldn't get your point. My point is whereas all the arteries carry oxygenated blood from the heart, and all the veins carry de-oxygenated blood to the heart, the pulmonary artery and the pulmonary vein do exactly opposite. What it means is that the pulmonary artery and the pulmonary vein do not conform to that definition. So they are exceptions.

TS:
You'll never encounter such a question on your paper. Rest assured.

Sorry! Got your point now. They are exceptions when we talk in terms of [I]oxygenated/de-oxygenated blood[/I]. Otherwise, all the arteries including the pulmonary artery carry the blood away [B]from[/B] the heart. And all the veins including the pulmonary vein carry the blood [B]to[/B] the heart. The difference being that the pulmonary artery carries the de-oxygenated blood, unlike other arteries which carry oxygenated blood. The same is the case with the pulmonary vein.

These vessels are 'defined' as those that carry blood to the heart and those that carry blood away from the heart. Their general characteristics include that arteries generally carry oxygenated blood and veins generally carry deoxygenated blood , with the exception of the pulmonary artery and veins. The reversal of function is not an exception to their definition but an exception to their characteristics. You mentioned it being an exception to the definition. It's a minute difference and probably doesn't even matter but i just wanted to clear the concepts of the the person making the enquiry.
An earlier typo may have made my answer somewhat hazy, i typed in 'now' instead of 'not'. Quote correction " The pulmonary artery carries deoxygenated blood away from the heart to the lungs and the pulmonary vein returns oxygenated blood to the heart from the lungs. Generally, arteries carry oxygenated blood and veins carry deoxygenated blood but that is 'NOT' how they're defined.
Again, it's a minor difference but i wanted the person asking to have a clear concept of it.

Yes. Sorry i just saw your other reply and i'd already written in a reply by then.

Thanks!
 

[QUOTE=candidguy;402298]
TS:
You'll never encounter such a question on your paper. Rest assured.[/QUOTE]

Well, I have no idea if this question is expected in paper. But science is a subject which needs a conceptual understanding. There are many things in science which you need to understand the actual concept of. I asked the question about pulmonary vessels with the same thought. Thanks for your participation candidguy.

[QUOTE=Asad Shafiq;402486]These vessels are 'defined' as those that carry blood to the heart and those that carry blood away from the heart. Their general characteristics include that arteries generally carry oxygenated blood and veins generally carry deoxygenated blood , with the exception of the pulmonary artery and veins. The reversal of function is not an exception to their definition but an exception to their characteristics. You mentioned it being an exception to the definition. It's a minute difference and probably doesn't even matter but i just wanted to clear the concepts of the the person making the enquiry.
An earlier typo may have made my answer somewhat hazy, i typed in 'now' instead of 'not'. Quote correction " The pulmonary artery carries deoxygenated blood away from the heart to the lungs and the pulmonary vein returns oxygenated blood to the heart from the lungs. Generally, arteries carry oxygenated blood and veins carry deoxygenated blood but that is 'NOT' how they're defined.
Again, it's a minor difference but i wanted the person asking to have a clear concept of it.[/QUOTE]

Thanks a lot for making my concept clear. Here is what I understand why these vessels have twisted names:

Generally arteries carry blood away from heart to all parts of body and veins carry blood from lungs to heart. But in case of pulmonary vessels the situation is reverse.

Deoxygenated blood enters heart's right auricle from upper and lower parts of body through veins and then it flows into right ventricle through a valve. When the ventricle contracts, the de-oxygenated blood is pumped out of heart to lungs for re-oxygenation. [B]Pulmonary artery is an artery because it is a vessel coming from your heart. [/B]

Once the blood reaches lungs, it is reoxygenated and carried to heart through pulmonary vein. It opens into left auricle and then flows into left ventricle through a valve. Then, blood is pumped out of heart as the result of contraction of left ventricle and supplied to all parts of body. [B]The pulmonary vein is a vein simply because it is a vessel returning to your heart.[/B]
[I]So, both pulmonary artery and pulmonary should not be understood in terms of oxygenation status, but rather in terms of blood flow in relation to heart.[/I]

I have just viewed a flow diagram which further clarifies the matter. I knew about the said vessels in crude terms before the discussion.

Thanks for contributing to my knowledge Asad Shafiq.

[B]Regards[/B]

[QUOTE=candidguy;402298]Couldn't get your point. My point is whereas all the arteries carry oxygenated blood from the heart, and all the veins carry de-oxygenated blood to the heart, the pulmonary artery and the pulmonary vein do exactly opposite. What it means is that the pulmonary artery and the pulmonary vein do not conform to that definition. So they are exceptions.

TS:
You'll never encounter such a question on your paper. Rest assured.[/QUOTE]
its very well explained by Mr.asad that oxygenated blood is not the criteria of being an artery...its the "taking away"...and "taking to" phenomen.....Pulmoneary artery takes pumped blood away from heart....hope i explained...

[QUOTE=azeegum;402237]Dear friends! Please solve my following confusion:

Artery is a blood vessel that carries oxygenated blood from heart to all parts of the human body while vein brings de-oxygenated blood from the body cells to the human heart. The function of both is clearly defined. Now the question is [B]why Pulmonary Artery carries de-oxygenated blood from the heart to the lungs and a pulmonary vein brings oxygenated from the lungs to the heart?[/B]
Why both vessels have different functions here or why both have twisted names here?

Knowledgeable members are requested to explain it.

Thanks and regards[/QUOTE]
My dear, confusion lies in the definition of an artery and vein.. Actually an artery is a vessel that carries blood (whether oxygenated or deoxygenated) away from the heart and a vein is a vessel that carries blood back (whether oxygenated or deoxygenated) to the heart.. As pulmonary artery carries blood from heart thus it is called an artery, though it carries deoxygenated blood.. and the opposite is that with the pulmonary vein..
Hope the confusion is cleared now..
Regards..

Moreover, blood is oxygenated somewhere; obviously in lungs, and it will be oxygenated if it is delivered to lungs plus pulled back to heart for circulation. Both of these functions are done by the pulmonary artery and vein. N consider the definition mentioned in above post.

[QUOTE=Da Skeptic;402672]My dear, confusion lies in the definition of an artery and vein.. Actually an artery is a vessel that carries blood (whether oxygenated or deoxygenated) away from the heart and a vein is a vessel that carries blood back (whether oxygenated or deoxygenated) to the heart.. As pulmonary artery carries blood from heart thus it is called an artery, though it carries deoxygenated blood.. and the opposite is that with the pulmonary vein..
Hope the confusion is cleared now..
Regards..[/QUOTE]

[QUOTE=Abdussamad Chaudhary;402680]Moreover, blood is oxygenated somewhere; obviously in lungs, and it will be oxygenated if it is delivered to lungs plus pulled back to heart for circulation. Both of these functions are done by the pulmonary artery and vein. N consider the definition mentioned in above post.[/QUOTE]

Thanks to both of you. I'm no more confused about the pulmonary vessels. I've also got the answer to my query under the following thread.
[url]http://www.cssforum.com.pk/css-compulsory-subjects/everyday-science/60074-pulmonary-artery-pulmnary-vein.html[/url]
Thanks for your participation too.

[B]Regards[/B]