Why does blood clot when it is placed on a glass slide?

why the blood clots outside our body?suppose when its put on a glass slide or it drops in the ground,it clots.why?

13 Comments

SkateRForeveR
on February 8th, 2012

Because of its exposure to the air.
Gunship
on February 8th, 2012

The blood contains white cells, red cells ,plasma,heamaglobin,when these things are not exposed to air the blood remains as it is.When the body cuts and it is exposed to air,the plasma,do some chemical reaction and the blood clots.For to clot the blood,Vit.’K’ needed.Some times blood also clot within the body,like in an accident ,after injury,some times blood clot in head,if it si an head injury,and at that time ,when the blood comes out of it’s vessel,it clots due to de-oxidisation.
Gideeup
on February 8th, 2012

Well this isn’t exactly my section of expertise. But i believe that it is because when the blood is exposed to air (all of the contents of it including O2) are exposed to the red blood cells. The Hemoglobin then bonds with the O2 turning it bright red as it is rich with oxygen. Naturally, blood will thicken and ‘coagulate’. Your body’s blood coagulates when it is exposed to the outside because if you didn’t coagulate your blood, you would bleed to death from a somewhat large cut on your arm or something like that. That disorder is called Hemophilia. The royal family of Russia (Czar Nicolas’ family) had a long line of hemophiliacs. His son had Hemophilia also. Hope this all answers some sort of your question.
ReadyToLaunch
on February 8th, 2012

Blood cannot clot inside the blood vessels because of the presence anticoagulants, like Heparin. When blood comes out, the heparin in it gets destroyed on exposure to air.

Generally, blood doesn’t clot on glass slide, it just dries up loosing water. Clotting and drying are different process. Clotting involves enzymatic action forming fibrin mesh where blood cells get trapped and entangled to form the clot. Drying is simply loosing water from the blood, forming a dried mass.

Negligible amount of blood clots on glass slide because the enzymes required for clotting are already pesent in the blood. When blood is taken from a person, Thromboplastic activity comes into play and triggers the clotting mechanism.

I am not describing the clotting process. I think you know it.
Xfactor
on February 8th, 2012

due to presence of clotting factor,vitamin k helps the blood to clot
Fractalfallout
on February 8th, 2012

Whenever the blood get exposes to air, the platelets are the responsible component of the blood clot. If it doesn’t clot, blood keeps oozes from the wound and it will prove fatal at the end.*
TotallyChilled
on February 8th, 2012

It has nothing to do with exposure to air. In the body, the clotting process is started when a plasma protein called Factor XII (also called “Hageman Factor”) bumps into a molecule that changes it’s shape so that it becomes “activated.” In our body, it is commonly believed that collagen from injured tissue provides the molecules that change the shape of Factor XII, but recently scientists in Japan and Germany are saying that it is RNA that is released into the blood when cells are damaged. Once the Factor XII is activated, it starts a whole cascade of other reactions with other proteins that eventually leads to the forming of fibrin (the clot strands) which forms the clot.

It turns out that glass (and certain types of clay) are similar enough in shape and charge profile to collagen and RNA that when the Factor XII bumps into it, the glass activates the Factor XII just like collagen and RNA do. One of the standard methods to test how well your blood clots is to stab your finger with a needle, get some of the blood into a teeny little glass tube called a glass capillary tube, wait a few minutes, and then break the tube in half. If the blood between the two broken halves is stringy, your blood is clotting well. No oxygen involved: just glass.

Good luck!!
PassionForDance
on February 8th, 2012

it is not always it clot outside. some times inside too.
heparin prevent its coagulation inside body.it has a defined mechanism can be get 4m book.
Tuskey
on February 8th, 2012

generally blood clots occur to stop the flow of blood, the blood reacts with the oxygen in air , that is ,the fibrin present in the blood reacts to form the clot. This fibrin is activated bythe thrombocytes present in the blood fluid.
Julie Ann
on July 1st, 2010

okay…so I had a friend ask me why blood clots outside of the body as opposed to inside the body and he said not to look at it in medical terms. I said, “Because of the activation of thrombin.”(He said, That is from a medical standpoint.”) I said, “Because of the constant movement of your blood.” (He said, “You can constantly move it in a tube back and forth and it still clots.”)…I then said, “Because the veins are closed off and there is no break in them.”-close to what I said previous and- (He said i was getting closer.)…So what else could it be? I’m just seeing what other people think about this in non-medical terms. And I want to get this right to prove I know just as much as he does.(He’s going to med. school, I’m in nursing school!) Trust me…it’s a pride thing ha ha! thanks!
ScienceStudent
on January 7th, 2011

TotallyChilled has the right idea. It is nothing to do with air. If you place blood on plastic there will be no clot formation. Blood acts differently when placed on glass and when placed on plastic.

Thanks, TotallyChilled!
Bipin Muktan
on January 27th, 2011

In-vivo, the blood is not clotted because of different mechanisms, like smooth surface of endothelium, presence of factors such as Antithrombin III, heparin, Proten C, Protein S, which has antithrombin activity. Antithrombin III is secreted by endothelium lining. when blood comes outside the body there is only small amount of heparin and no antithrombin III present. Heparin requires antithrombin for its activity. and also platelet release the factor, protamine that inhibits heparin, in-vitro. So blood is clotted outside the body.
garima
on November 15th, 2011

Though many of the above views brought me to raise many questions but i found none of the above to the perfect answer. I exactly want to know clear cut view of this phenomenon. Being specific only to glass or oxygen or clotting factors may not fulfil the requirement of question. That is what I think . Can somebody tell me the answer. What is that which will be different outside the body except temp. or may be activation or deactivation of some factors. platelets do have some significance. or and also want to know about internal blood clotting