Pathophysiology - Cell Death

Cell Death

1. Apoptosis
• Involves controlled cell auto-destruction
• Means by which the boy removes and replaces cells that have been produced in excess, developed improperly, have genetic damage or worn out
• Programmed destruction of cells during embryonic development
• Example heart begins as a single pulsating tube and is gradually modified to become a 4-chambered heart
2. Necrosis
• Cell death in an organ or tissue that is still part of the living person
• Involves unregulated enzymatic digestion of cell components, loss of cell membrane integrity with uncontrolled release of the products of cell death into the intracellular spaces and initiation o inflammatory response
• Interferes with cell replacement and tissue regeneration
• Liquefication necrosis
• Occurs when some cells die but their catalytic enzymes are not destroyed
• Coagulation necrosis
• Results from hypoxic injury and in infarcted areas (tissue death)
• Caseous necrosis
• Soft, cheese-like center, associated with tubercular lesions
3. Gangrene
• considerable mas of tissue undergo necrosis
• Dry
• Part becomes dry, shrinks, skin wrinkles, dark brown or black in color
• Slow spread, line of demarcation between gangrenous and healthy tissues
• No interferes with venous return but interference with arterial blood supply
• Moist/Wet Gangrene
• Cold, swollen, pulseless, moist, black, under tension
• Foul odor cause by bacterial action
• Do demarcation, rapid spread, death
• Interfere with venous return
• Gas gangrene
• Clostridium bacteria: anaerobic spore- forming organism in soil
• Dirt and debris are embedded
• Bacteria dissolve cell membrane, massive spreading edema, hemolysis of RBC, renal toxicity
• Bubbles of hydrogen sulphide gas form in muscles –fatal