Practical Pathophysiology Lab 2 PDF

Practical Pathophysiology Lab 2 The third stage Prof Dr.Shaimaa A.Shlash 1 Cell injury and cell death CELL INJURY AND DEATH Cells can be injured in many ways. The extent to which any injurious agent can cause cell injury and death depends in large...

Practical Pathophysiology Lab 2 The third stage Prof Dr.Shaimaa A.Shlash 1 Cell injury and cell death CELL INJURY AND DEATH Cells can be injured in many ways. The extent to which any injurious agent can cause cell injury and death depends in large Loading… measure on the intensity and duration of the injury and the type of cell that is involved.  Causes of Cell Injury Cell damage can occur in many ways. For purposes of discussion, the ways by which cells are injured have been grouped into five categories: (1) injury from physical agents (2) radiation injury (3) chemical injury (4) injury from biologic agents (5) injury from nutritional imbalances. Cell injury either: Reversible………sublethal Irreversible………….lethal Reversible cell injury. In early stages or mild forms Loading… of injury, the functional and morphologic changes are reversible if the damaging stimulus is removed. Cell death. With continuing damage the injury becomes irreversible, at which time the cell cannot recover and it dies.  In each cell line, the control of cell number is regulated by a balance of cell proliferation and cell death. There are two principal types of cell death necrosis and apoptosis.  Apoptosis Apoptotic cell death involves controlled cell destruction and is involved in normal cell deletion and renewal. Necrosis Necrosis refers to cell death in an organ or tissue that is still part of a living person.  Types of necrosis Coagulative necrosis: characteristically occurring in the heart, kidney and spleen, but it may occurring in most tissues. **Dead tissue is initially swollen, gray and firm mass, but later it become soft as a result of digestion by macrophages  Coagulative necrosis Figure -1 This cross section reveals a large myocardial infarction involving the anterior left ventricular wall and septum Figure -2 Ischemic necrosis of the myocardium. A, Normal myocardium. B, Myocardium with coagulation necrosis (upper two thirds of figure), showing strongly eosinophilic anucleate myocardial fibers. Leukocytes in the interstitium are an early reaction to necrotic muscle. Compare with A and with normal fibers in the lower part of the figure. Liquefaction or colliquative necrosis This characteristically occurs in the brain , its cellular destruction by hydrolytic enzymes. Loading… Liquefactive necrosis Figure -3 Figure -4 liquefactive necrosis. focus of liquefactive necrosis in the kidney caused by fungal infection. The focus is filled with white cells and cellular debris, creating a renal abscess.  Caseous necrosis : This a characteristics of tuberculosis (TB). There are variable amounts of fat and an appearance of cottage cheese ( cheesy material by infiltration of fatlike substances ) hence the term caseation Figure -5 A tuberculous lung with a large area of caseous necrosis. The caseous debris is yellow-white and cheesy. 4-Fat necrosis Adipose tissue damage by : Direct trauma : Enzymatic lipolysis :in acute pancreatitis, Insoluble Ca+2 salts: Appear as whitish chalky areas scattered within normal adipose tissue.[saponification]. Figure -6 Foci of fat necrosis with saponification in the mesentery. The areas of white chalky deposits represent calcium soap formation at sites of lipid breakdown.  Gangrene necrosis Necrosis tissue is invade by putrefaction organisms notably clostridia. The tissue appears green or black because of the breakdown of hemoglobin.  FIGURE -7 Gangrenous toes Figure-8 gangrene  Fibrinoid necrosis Sometimes the small arteries and arterioles can be damaged so severely in malignant hypertension that they demonstrate necrosis with a pink fibrin-like quality that gives this process its name--fibrinoid necrosis Thank you