Types of Necrosis: unprogrammed cell death Flashcards
What is necrosis?
Accidental, unprogrammed cell death in response to irreversible cell injury
What cellular components are damaged and so trigger necrosis?
Membranes
What 2 responses are triggered by damage to cell membranes in necrosis?
Lysosomal digestion, cell leakage triggers inflammatory response
Are there different types of causes for necrosis?
Cause is always pathological
Give 4 examples of pathological causes that trigger necrosis?
Ischaemia, toxins, trauma, infections
How do calcium ions cause mitochondrial damage which leads to necrosis?
Calcium ions enter cell which stimulates Mitochondrial Permeability Transition Pores (MPTP) to open in inner membrane, so ATP is depleted
How does calcium cause DNA damage which leads to necrosis?
Calcium activates enzymes that cause DNA damage, as well as nuclear and membrane damage
How does free radical damage occur, that leads to necrosis?
Free radicals are highly reactive unpaired electrons that modify adjacent molecules eg. proteins, nucleic acids, lipids
How do free radicals affect interacting molecules in auto-catalytic reactions?
Converts interacting molecules into free radicals
What are the 2 ways in which antioxidants protect against free radical damage, preventing necrosis?
Block free radical formation, inactivate free radicals
What 3 vitamins are antioxidants that protect against free radical damage, preventing necrosis?
Vitamins A,C,E
What substance is an antioxidant that protects against free radical damage, preventing necrosis?
Glutathione
Which 2 immune cells produce ROS free radicals in large amounts?
Neutrophils, macrophages
What is coagulative necrosis caused by?
Ischaemia
What are the 2 microscopic features of coagulative necrosis?
Cells have lost their nuclei, eosinophilia (hyper-pink H&E stained cytoplasm)