LG6.10 pathology part III cell death, tissue necrosis and apoptosis Flashcards
Differentiate between necrosis and autolysis
Necrosis is seen in the living (with inflammation) and autolysis is seen in tissues after death.
What are the 4 types of cell necrosis?
Coagulative, fatty, liquifactive, caseous
What is the most common type of necrosis? How and where does it occur; provide at least one example?
Coagulative
Occurs when cell proteins are denatured, most commonly cause by anoxia
Typically occurs in solid internal organs
Examples: heart, liver, speen…
Best example: heart during a MI (anoxic conditions)
What’s a hallmark of acute inflammation? Why is this hallmark helpful in forensic pathology?
Neutrophil recruitment
If neutrophils are present on a cadaver (dead=pus) they were recruited by acute inflammation and are features of necrosis. This means the inflammation occurred before death.
What is liquefactive necrosis and what are some examples of it?
Refers to a process by which dead cells liquefy under the influence of certain cell enzymes.
It occurs most often in the brain where the brain cells lose their contours and liquefy, or it can be seen in certain bacterial infections in which a cavity may develop. (abscesses in the lungs; staff aureus)
What is caseous necrosis and what are some examples of it?
A form of coagulative necrosis in which a thick, yellowish, cheesy substance forms.
Is typically found in Tuberculosis, characterized by the development of lung granulomas, inside of which can be found caseous necrosis. This is called a Ghon Complex, and usually heals, containing the infection.
TB is buried inside this necrosis and this is the reason why long term therapy is needed (to penetrate the necrotic shell)
What is fatty necrosis and what are some examples of it?
A specialized form of liquefaction necrosis caused by the action of lipolytic enzymes
It is limited to fat tissue, usually around the pancreas, where enzymes are released into the adjacent fat tissue, usually after rupture of the pancreas (trauma, acute pancreatitis), causing degradation of fat into glycerol and free fatty acids. The free fatty acids rapidly bind with calcium, forming soaps, causing white, calcified specks.
What’s the difference between wet and dry gangrene?
Under what conditions does this usually happen?
The bacterial infection of coagulated tissue leads to inflammation and a secondary liquefaction clinically known as wet gangrene. If the necrotic tissue dries out, it becomes black and mummified (dry gangrene)
Such infections frequently occur after an infarction of the intestines or in a limb and are usually caused be atherosclerosis or diabetes.
Peripheral neuropathy and ischemia in a diabetic may prevent detection of injury and retard healing (high sugar can retard neutrophils), opportunity for bacterial infection.
Define and give examples of dystrophic calcificaitons
Dystrophic calcification: Necrotic tissue attracts calcium salts and frequently undergoes calcification. Extra-cellular calcium deposit into dead or dying tissue; grainy or rock hard.
atherosclerotic plaque, a cancerous mass of the breast, aortic or mitral valve stenosis.
Define and give examples of metastatic calcifications and explain how it’s different from dystrophic calcificaiton
Reflects deranged calcium metabolism (not cell injury), usually associated with increased serum calcium levels, leading to deposition of calcium in other locations.
Seen in various disorders including Hyperparathyroidism, Vitamin D toxicity, and Chronic Renal Failure.
Deposits in gallbladder, kidney, and bladder from salt precipitation
Define apoptosis its cause and pathologic features
Apoptosis is a form of programmed cell death which is an energy dependent process to switch off cells. Can be part of normal development or a pathologic processes (radiation or chem treatment which damages cells)
Pathologic features include: nuclear frag, pyknosis (condensed nucleus), cytoplasmic blebs…
