The pain of falling on the head, everyone has experienced.
When the wound bleeds, you can't help grinning, and at this time, in the veins, a group of cute "repairmen" have taken action, rushing to the wound, and at the first time, trying to put a "Band-Aid" for you.
They are cute "platelets".
Platelets, a member of the blood component, they are short, round, soft and cute.
You may not imagine that in a healthy adult, there are 100 million platelets in the body, constantly "patrolling" along the sides of the lining of blood vessels every day.
They carry a variety of "detectors" to detect the situation, the most important of which is the platelet membrane glycoprotein Ib (GPIb).
When you are injured and bleeding, there is a barrier called endothelial cells in the blood vessels, and when the endothelial cells are damaged, a factor code-named "vWF" is exposed, at which point the detector in the platelet hand comes into play:
Not only can it be detected, but it can also be combined with it, so that platelets will be adhered to the wound!
Platelets, quite team spirit, although they have no advantage in stature, short stature, short arms, but in order to protect your peace, they will "weave the net":
With the help of integrin alphaIIbβ3 receptors, they bind to fibrinogen or vWF so that they are joined together and woven into a Band-Aid that seals the wound from inside the blood vessel [1].
In order for the walls of the blood vessels to return to their integrity, they begin to release signals to "ask for help."
1
Organizer Mobilizer – P-Select Element
Activated platelets expose P-selectin, which gathers larger white blood cells, blocking the wound and removing bacteria.
2
"Signal flares" – such as coagulation factor V and negatively charged phospholipids
Unleash a "signal bomb" – activate thrombin, which in turn further activates platelets, attracts companions, and at the same time, summons more white blood cells.
When thrombin is activated in a waterfall, a fibrin network is formed at the wound, which traps other blood cells to form clots, reinforces platelet emboli, completely seals the blood vessels in the injured area, and completes hemostasis [2].
If you always:
There was no injury but inexplicably nosebleeds
It is also easy to bleed gums with a soft bristle brush
I feel that even if I don't bump on my body, I will be blue and purple
Then be careful, this may be thrombocytopenia [3]!
A normal platelet count (150 to 400) × 19/L, and if it is below 150× 109/L is called thrombocytopenia [4].
In daily life, there are always various causes of vascular damage:
It may be a cold and diarrhea, and the bacterial virus enters the blood to destroy the blood vessels;
It may be a collision, an external force squeezing damaged blood vessels;
It may also be that nothing is done, and the high-speed flow of blood has caused a shock to the blood vessels.
Vascular damage exists at any time, and if there are too few Band-Aids "platelets" in the body to repair the wound in time, various bleeding symptoms mentioned above will occur.
Thrombocytopenia is divided into 3 degrees: mild to moderate, and the lower the number of platelets, the more severe it is.
Mild, moderate thrombocytopenia:
Nosebleeds of unknown causes, bleeding gums, bruising occurs when they are slightly bumped, and there is a "blue and purple piece" on the skin.
Severe thrombocytopenia:
In addition to the above symptoms (mild and moderate thrombocytopenia), life-threatening conditions such as hematemesis, blood in the stool, and intracranial hemorrhage may occur even in the absence of an underlying disease.
Of particular note are:
If there are often unexplained nosebleeds, bleeding gums, ecchymosis of the skin, accompanied by fever, fatigue, shortness of breath and other symptoms, to highly suspect leukemia, aplastic anemia and other very difficult blood diseases, it is recommended to go to the regular hospital hematology department immediately!
These "little angels" in your body that you can't see will not hesitate to "sacrifice themselves to save each other" when you are injured, and they will do their best to protect you.
On the road to growth, there are always bumps
But there is always someone silently guarding you
Don't be afraid, be brave and rush forward
Contributing Author: Ruiqi Zhu
Resident physician of the Department of Hematology, Union Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology
bibliography
[1] Tomaiuolo, M., Brass, L. F. & Stalker, T. J. Regulation of Platelet Activation and
Coagulation and Its Role in Vascular Injury and Arterial Thrombosis. Interv Cardiol Clin
6, 1-12, doi:10.1016/j.iccl.2016.08.001 (2017).
[2] Holinstat, M. Normal platelet function. Cancer Metastasis Rev 36, 195-198,
doi:10.1007/s10555-017-9677-x (2017).
[3] Lee, E. J. & Lee, A. I. Thrombocytopenia. Prim Care 43, 543-557,
doi:10.1016/j.pop.2016.07.008 (2016).
[4] Kaushansky, K. et al. "Williams Hematology (9th Ed.)" (2016). Faculty Bookshelf. 72.
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