[Solved] Nitroglycerin SL tablets should be used immediately if a patient experiences angina. Micrographs: Photographic or digital images taken using a microscope to magnify objects that are too small to be seen by the naked eye. Megakaryocyte: A large bone marrow cell responsible for the production of blood thrombocytes (platelets), which are necessary for blood clotting. Monocyte: A monocyte is a type of white blood cell part of the human body's immune system that fights off viruses, bacteria, and fungi; these cells can differentiate into macrophages and dendritic cells. Hematocrit Value: The proportion of blood volume that is occupied by red blood cells, expressed as a percentage.