Justin Bieber was born March 1, 1994 and grew up in Stratford, Ontario, Canada. Justin Bieber is 23 years old. At the age of 12 he entered a local singing competition against others who had significantly more experience and the benefit of vocal coaches. Justin Bieber came in second place singing Ne-Yo's So Sick..
Platelet. An irregularly shaped cell-like particle in the blood that is an important part of blood clotting. Platelets are activated when an injury causes a blood vessel to break. They change shape from round to spiny, sticking to the broken vessel wall and to each other to begin the clotting process.
Red blood cells carry oxygen to all parts of the body. White blood cells help fight infection. Platelets are tiny cells that have a big job in stopping bleeding. Proteins in the blood called clotting factors work to form a clot. In order to understand bleeding disorders, you have to know how the proteins and the platelets in the blood work together. Our bodies make platelets inside the marrow of our bones. Platelets are disc shaped cells that are so small they can only be seen with a microscope.