Morphology of Necrosis скачать в хорошем качестве

Morphology of Necrosis

This video covers the morphology of necrosis and the varied appearance of the different types of necrosis (coagulative, liquefactive, gangrene, caseous, fat and fibrinoid). The variation in morphology between these different types of necrosis is often due to the location of, tissue involved or the underlying disease process. In coagulative necrosis, most often exemplified due to ischemia following vessel obstruction, tissue architecture can be preserved for several days. This is due to structural protein and enzymatic denaturation that occurs within the necrotic cells which prevents proteolysis of dead cells. Eventually this necrotic debris is phagocytosed by leukocytes migrating into the necrotic tissue. In liquefactive necrosis, most often seen in hypoxia death of CNS cells and in bacterial infections elsewhere in the body, dead cells are digested and tissue becomes a liquid, viscous mass. The necrotic tissue becomes a creamy yellow material called pus which is often composed of dead leukocytes. Gangrenous necrosis is not a specific pattern of cell death but instead is a combination of the previous two. Most often seen following injury to a limb, ischemia leads to coagulative necrosis of the limb. On top of that, a concurrent bacterial infection in the affected limb also leads to liquefactive necrosis. Caseous necrosis, most often associated with tuberculosis, is a mass of white/yellow, friable material which is often likened to a crumbly cheese (thus the name caseous). The necrotic mass is a collection of fragmented, lysed cells and debris within an inflammatory border. This focus of inflammation is known as a granuloma. Fat necrosis is a common term in medical language but does not represent a specific pattern of necrosis. Instead, it refers to a focal area of fat destruction, often due to the release of active pancreatic enzymes (like in cases of acute pancreatitis). These enzymes break down surrounding fat cells and lyse the triglycerides contained within. The free fatty acids are then free to combine with calcium to produce chalky white areas which are visible to the eye. Fibrinoid necrosis is a special type of necrosis which is typically seen in vascular immune reactions when complexes of antigens and antibodies become embedded in vessel walls. Fibrin also leaks into these areas where complexes are embedded which creates a bright pink (eosinophilic) appearance on histology. Necrotic cells and tissue will eventually be cleaned up by leukocytes (via enzymatic digestion and phagocytosis). If the necrotic debris is not removed relatively quickly, this dead tissue can become a centerpoint for the deposition of calcium and other minerals. This process of hardening and calcifying tissue is known as dystrophic calcification. 0:00 Intro 0:08 What is necrosis? 1:54 Coagulative necrosis 2:48 Liquefactive necrosis 3:38 Gangrenous necrosis 4:24 Fat necrosis 5:01 Caseous necrosis 5:29 Fibrinoid necrosis 5:55 Dystrophic calcification Photos from: Robbins and Cotran Pathologic Basis of Disease, 9th Edition علاء CC BY-SA 3.0 https://creativecommons.org/licenses/..., via Wikimedia Commons ❤️ If you find my content helpful, become a channel member -    / @canadianpathassistant9066   WHO AM I: I'm a full time Pathologists' Assistant working in western Canada. I'm making videos about becoming a PA, giving you tips about school and letting you know what this career is like. You can also visit me at http://www.canadianpathassistant.com/ GET IN TOUCH: If you'd like to talk, I'd love to hear from you! Leaving a comment will be the quickest way to get a response but if you have a longer question or want to keep your question private, feel free to email me at [email protected].