Cell Injury Flashcards
The patient on the left has a markedly cyanotic (blue) tongue compared to the normal patient’s tongue on the right. Central cyanosis is due to an increased amount of unoxygenated hemoglobin (Hgb) in the blood (called deoxyhemoglobin). This translates into a decrease in the oxygen saturation of blood (percentage of the heme groups on Hgb occupied by oxygen). Central cyanosis is due to any cause of hypoxemia (e.g., respiratory acidosis, ventilation/perfusion/diffusion problems in the lungs, right to left shunting of blood in cyanotic congenital heart disease), since a low arterial PO2 automatically lowers the amount of O2 that diffuses into the RBC to bind to heme. Peripheral cyanosis refers to vasoconstriction of the blood vessels in the skin with central shunting of the blood (e.g., hypothermia). The skin is cyanotic, however the mucous membranes are pink.
The brown pigment noted in the hepatocytes (arrow) represents lipofuscin (wear and tear pigment). Lipofuscin is the end product of free radical injury of cells and autophagy (destruction of cell organelles and structural proteins in cells undergoing atrophy). Grossly, an excess of lipofuscin produces a brown discoloration, hence the term brown atrophy. Lipofuscin is commonly found at autopsy in elderly patients.
The arrow points to an anucleate, deeply eosinophilic staining cell that is retracted away from the other cells. The last phase of destruction of this cell will be fragmentation into apoptotic bodies containing bound packets of organelles which will be phagocytosed and destroyed in the lysosomes of macrophages and neighboring cells. Note that there is no inflammatory infiltrate around the cell
The anterior part of the heart is at the bottom of the slide. The left ventricle is on your left and the right ventricle on your right. The arrows point to a pale infarct in the entire anterior part of the heart and anterior two-thirds of the interventricular septum. The patient had a platelet thrombus in the left anterior descending coronary artery, which supplies blood in the same distribution outlined by the infarction. Coagulation necrosis is the underlying pathologic process. The infarct is pale owing to the dense consistency of muscle so that extravasated RBCs from necrotic vessels remain localized and are unable to percolate through the tissue
