1.1 POJA-L755+868. Platelets (peripheral blood, human)
1.1 POJA-L755+868
Title: Platelets (peripheral blood, human)
Description: Electron microscopy.
These anucleate cells (2-4 mm) are derived from cytoplasmic fragments of a megakaryocyte and when free floating in the peripheral blood they develop thin extensions. These platelets contain among others few mitochondria (1), microtubules (2), glycogen (3), small vacuoles (4, open canalicular system, OCS), elements of dense smooth tubular system (7). The arrow indicates the open connection of the OCS with the environment. (x) indicates a cross-section of the outer blood compartment.
Homogeneous electron-dense d granules (5) contain plasma-absorbed serotonin, calcium ions, ADP and ATP etc. The electron-grey granules (6) with a dark centre (a-granula) are variable in size and contain among others platelet-derived growth factor, factor VIII (von Willebrand), thrombospondin, fibronectin, fibrinogen.
Background: In a clotting process due to adherence to collagen exposed receptors for factor VIII platelets change their shape becoming spherical and develop numerous long thin cytoplasmic processes that interlinked with other platelets. The granular contents are released via the open canalicular system (4 and ↓) and the clotting cascade is activated due to adhesion of other platelets under the influence of ADP, calcium ions etc.
Keywords/Mesh: blood, bone marrow, platelet, megakaryocyte, histology, electron microscopy, POJA collection
Title: Platelets (peripheral blood, human)
Description: Electron microscopy.
These anucleate cells (2-4 mm) are derived from cytoplasmic fragments of a megakaryocyte and when free floating in the peripheral blood they develop thin extensions. These platelets contain among others few mitochondria (1), microtubules (2), glycogen (3), small vacuoles (4, open canalicular system, OCS), elements of dense smooth tubular system (7). The arrow indicates the open connection of the OCS with the environment. (x) indicates a cross-section of the outer blood compartment.
Homogeneous electron-dense d granules (5) contain plasma-absorbed serotonin, calcium ions, ADP and ATP etc. The electron-grey granules (6) with a dark centre (a-granula) are variable in size and contain among others platelet-derived growth factor, factor VIII (von Willebrand), thrombospondin, fibronectin, fibrinogen.
Background: In a clotting process due to adherence to collagen exposed receptors for factor VIII platelets change their shape becoming spherical and develop numerous long thin cytoplasmic processes that interlinked with other platelets. The granular contents are released via the open canalicular system (4 and ↓) and the clotting cascade is activated due to adhesion of other platelets under the influence of ADP, calcium ions etc.
Keywords/Mesh: blood, bone marrow, platelet, megakaryocyte, histology, electron microscopy, POJA collection