Freeze_etching studies of human platelets

The freeze-etching technique was used to study morphologic features of nor-mal human platelets. A well-developed canalicular system was demonstrated within the platelet, with communication to the plasma surface of the platelets and with direct contact of the canali-culi with organelles. Cross-section fractures of granules revealed corn-partmentalization in some while others appeared homogeneous. Several types of filamentous structures were ob-served within the matrix of the platelet. Microtubular su,filaments were ap-proximately 80 A in diameter. Micro