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In a typical set of rules, a platelet donor must weigh at least 50 kg (110 lb) and have a platelet count of at least 150 x 10 9 /L (150,000 platelets per mm³). [2] One unit has greater than 3×10 11 platelets. Therefore, it takes 2 liters of blood having a platelet count of 150,000/mm³ to produce one unit of platelets.
Platelet concentration in the blood (i.e. platelet count), can be measured manually using a hemocytometer, or by placing blood in an automated platelet analyzer using particle counting, such as a Coulter counter or optical methods. [47] Most common blood testing methods include platelet count in their measurements, usually reported as PLT. [48]
The megakaryoblast is a platelet precursor that undergoes endomitosis to form megakaryocytes that have 8 to 64 nuclei. Megakaryocytes shed platelets into the bloodstream. β1-tubulin microtubules, which are found in megakaryocytes, facilitate this process of shedding platelets into the bloodstream. [5]
Red blood cells (RBCs), referred to as erythrocytes (from Ancient Greek erythros 'red' and kytos 'hollow vessel', with -cyte translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, [1] erythroid cells, and rarely haematids, are the most common type of blood cell and the vertebrate's principal means of delivering oxygen (O 2) to the body tissues—via ...
Hemoglobin has an oxygen binding capacity between 1.36 and 1.40 ml O 2 per gram hemoglobin, [23] which increases the total blood oxygen capacity seventyfold, [24] compared to if oxygen solely were carried by its solubility of 0.03 ml O 2 per liter blood per mm Hg partial pressure of oxygen (about 100 mm Hg in arteries). [24]
They circulate in the blood of mammals and are involved in hemostasis, leading to the formation of blood clots. Platelets release thread-like fibers to form these clots. The normal range (99% of population analyzed) for platelets is 150,000 to 450,000 per cubic millimeter. [6] If the number of platelets is too low, excessive bleeding can occur.
When red blood cell concentrates are produced from whole blood, the whole blood is first separated through centrifugation (usually between 3000 to 5000 x g). The red blood cells are denser than plasma and the other present blood cells (platelets, white blood cells) and settle at the bottom of the blood bag.
Platelets immediately form a plug at the site of injury; this is called primary hemostasis. Secondary hemostasis occurs simultaneously: additional coagulation factors beyond factor VII (listed below) respond in a cascade to form fibrin strands, which strengthen the platelet plug. [1] Coagulation is highly conserved throughout biology.