Cell Damage Flashcards
(45 cards)
What are the 3 cellular outcomes of prolonged decreased functional demand?
1) Atrophy (↓ cell size)
2) Involution/Hypoplasia (↓ cell no.)
3) Metaplasia
What are the 3 cellular outcomes of prolonged increased functional demand?
1) Hypertrophy (↑ cell size)
2) Hyperplasia (↑ cell no.)
3) Metaplasia
What is the difference between metaplasia and dysplasia?
Metaplasia transforms a cell from one form to another; caused by external stimulus; can be reversible; less likely to lead to cancer.
Dysplasia transforms a cell into an abnormal version of itself; caused by internal stimulus; is irreversible and more likely leads to cancer.
What can stimulate cellular metaplasia?
Injurious stimuli (eg. Gastroenteritis, H. pylori infection, CMV)
What are the 4 mechanisms of cell injury?
1) Cell membrane damage (eg. complement-mediated lysis via MAC, bacteria toxins, free radicals)
2) Mitochondrial damage (eg. Hypoxia, Cyanide poisoning)
3) Ribosomal damage (eg. alcohol in hepatocytes, antibiotics in bacteria)
4) Nuclear damage (eg. virus, radiation, free radicals)
How can increased cytosolic Ca2+ cause cell damage?
Ca2+ ions can activate hydrolytic enzymes
i) ATPase→↓ATP
ii) Phospholipase→↓phospholipids
iii) proteases → membrane dmg
iv) endonuclease → chromatin dmg
How can tissue ischaemia cause cell damage?
Decreased OXPHOS and ATP prod.
i) Ribosome detachment
ii) ↑ Anaerobic glycolysis → ↓pH
iii) ↓Na pump f(x) → cell swelling
Are all early cellular changes after injury reversible?
Yes
Are all late cellular changes after injury irreversible?
Yes
What factors determine whether cellular changes in response to injury are reversible or irreversible?
1) Type of injury
2) Exposure time
3) Severity
What are 4 early/reversible cellular changes after injury?
1) Cytoplasmic swelling & Vacuolation
2) Mitochondrial & ER swelling
3) Chromatin clumping
4) Fatty changes
What are 4 late/irreversible cellular changes after injury?
1) Densities in mitochondria
2) Cell membrane disruption
3) Lysosomal rupture
4) Atypical nucleus
4a) Pyknosis (nuclear shrinkage)
4b) Karyolysis (nuclear dissolution)
4c) Karyorrhexis (nuclear breakup)
How can fat change occur in hepatocytes?
Anythingthat changes FFA Ss or metabolism
1) DM/Starvation → change FFA Ss
2) Ethanol → ↑FFA Ss and ↓Esterification
3) Hypoxia → ↓FFA oxidation and ↓ esterification
4) Toxins → ↓FFA oxidation and ↓apoprotein availability
5) Protein malnutrition → ↓apoprotein availability
What are 2 cellular non-death responses to injury?
1) Cell stress response (↑exp. of protective proteins)
1a) molecular chaperones (refold misfolded proteins)
1b) Ubiquitination of damaged proteins
2) Autophagy (digest own organelles)
What are the histological characteristics of cell stress response?
Inclusion bodies (Aggregates of ubiquitin & damaged proteins)
eg. Mallory’s hyaline bodies in Hepatocytes with Alcoholic Liver Damage, Lewy Bodies in Substantia Nigra with Parkinson’s
What are the histological characteristics of Autophagy
Residual bodies (accumulation of lipofuscin: wear and tear pigment)
What are “wear and tear pigments”.
Lipofuscin
What are the 3 forms of cell death?
1) autolysis
2) apoptosis
3) necrosis
What are the differences between Autolysis, Apoptosis, Necrosis?
Autolysis is the death of tissues after the death of the organism.
Apoptosis is the death of cells in living tissues and programmed. It can be physiological or pathological.
Necrosis is the death of cells in living tissues and is always pathological.
Compare and contrast between Apoptosis and Necrosis.
Apoptosis:
- can be physiological or pathological
- membrane preserved
- no inflammation
- single cells
- active process
Necrosis:
- always pathological
- membrane breached
- inflammatory
- contiguous (connecting) cells
- passive process
Which form of necrosis is associated with ghost outlines?
Coagulative necrosis
What are 8 forms of necrosis?
1) Coagulative
2) Caseous
3) Liquefactive
4) Suppurative
5) Hemorrhagic
6) Fat
7) Gangrenous
8) Fibrinoid
Which form of necrosis is common secondary to hypoxia, ischaemia, infarction, and skin burns?
Coagulative necrosis
Which form of necrosis is associated with associated with friable and “cheesy” tissue?
Caseous necrosis
