Spleen

[Jokkon]

ah ic thank you
btw, when ppl donates blooddo they extract calcium from the blood to prevent clotting?

[mith]

where did you get the idea that calcium causes clots?

[Jokkon]

umm, i am just learning about fibrinogen, i thought that u need calcium+ thrombolplastin to activate prothrombin and turn it to thrombin and thrombin turns fibrinogen into fibrin?

[mith]

[quote=Wikipedia.com]
Contrary to popular belief, coagulation from a cut on the skin is not initiated by air or drying out, but it is because platelets adhere to and are activated by collagen outside the blood vessel and the skin. The activated platelets then release granules that contain pro-coagulant proteins furthering clotting.
[/quote]

The platelets must be activated to clot, the calcium is part of the clotting pathway but does not initiate it.

[opuntia]

Naah.

Not even towards the end of fetal life and in cases of bone marrow breakdown?

[Dr.Stein]

In fetus yes, but just for some periods, until their bone marrow is mature and can function properly. In grown-up individual, I don't think so. The production of all blood cells are originally and centralized from bone marrow, except the maturation of course, it can be done in peripheral circulation and tissues, thymus, spleen, and other secondary limphoid organs.

In the case of bone marrow disorder, the only way I know is via bone marrow transplantation. In this case spleen cannot take the function of bone marrow to produce blood cells. I still have no idea.

[Dr.Stein]

ah ic thank you
btw, when ppl donates blooddo they extract calcium from the blood to prevent clotting?

Simply the add external anticoagulant such as heparin or EDTA to the blood pocket prior to fill it with blood from donor.

[Jokkon]

so aht exactly is being extracted from the blood after theyt take it out from the donor?
its actually a multiple choice question on a test =D
the choices are iron calcium vitamin K, the other one i forgot
i chose iron, i don't know why, i think i got it wrong =(

[Dr.Stein]

Calcium

[mith]

ooh, I didn't know that, how do they extract the calcium? I assume they would be in ionic form

[Dr.Stein]

Calcium in blood is disolved in the plasma/serum, and yes it is in ionic form, Ca++. There are some techniques to extract element from its substance, but in general it is called as chromatography, e.g. HPLC, GC, TLC, etc.

But in the blood donation, I have no idea if they do this extraction. This definetely takes time and too expensive if everytime we work on blood donation we have to to extraction. As far as I know, the blood pocket (ampulla) already contains anticoagulant to prevent donor's blood from coagulation. This substance already contains anticoagulant factors, including calcium, thus the independent calcium extraction is not necessary I think.

[Jokkon]

noooo..
i knew it'd be calcium..., and yet i picked iron, how stupid could i possibly get.. why'd they take iron out...
thats why i hate multiple choice questions