Platelets derive from megakaryocyte proplatelets. Microtubules aggregate at one end of the cell cortex of a megakaryocyte as the cell extends pseudopods. As pseudopods extend further, they becomes thinner and ultimately branch and split into proplatelets. Platelet granules and organelles are transported along microtubules through the proplatelets into the nascent platelets. Ultimately, platelets release off the ends of the proplatelets.