Ch 2 Flashcards
(124 cards)
Causes of cell injury (7)
1.Oxygen deprivation
2.physical agents
3. Chemical/drugs
4.genetic
5.nutritional imbalances
6.infectious agents
7.immunologic
Give an example of hypoxia causing cell injury?
Acute Occlusion of blood vessels - ischemia leading to cell injury
Give an example of physical agents causing cell injury?
Trauma (mechanical), temperature (burns), sudden atmospheric pressure changes, electives shock
Give an example of immunologic agents that cause cell injury?
Viruses
Tapeworms
Parasites
Fungi
What time frame would ischemic changes be seen in light microscopy?
4-12 hrs after onset of ischemia
Is swelling of cell reversible?
Yes if happens in minutes
When does cell swelling become irreversible? (Timeframe)
1-2 hrs
In what order can you see changes in cells (chemical—>macro)
Minutes to hours:
1.biochemical
2.Ultrastructural
Hours to days:
3.Light micro
4.gross morphologic changes
What are features of necrosis:
1.cell size (swelling)
2.nucleus
3.plasma membrane
4.cellular contents
5.adjacent inflammation
6.physiologic/pathologic?
1.enlarged
2.karyorrhexis/pyknosis/karyolysis
3.disrupted
4.enzymatic digestion/leak out of cell
5.frequent
6.pathologic
What are features of apoptosis:
1.cell size (swelling)
2.nucleus
3.plasma membrane
4.cellular contents
5.adjacent inflammation
6.physiologic/pathologic?
1.reduced/shrink
2.fragmentation into nucleosome-size fragments
3.intact however altered structure
4.intact-may be released into apoptotic bodies
5.none
6.physiologic mainly, can be pathologic after cell injury (eg DNA damage)
Why do cells swell when injured?
Influx of water due to failure of ATP dependent Na-K channel (due to failure of mitochondrial oxyfative phosphorylation)
What effect does cell death have on tissues? (Colour, weight, turgor)
Pale
Heavier
Increased turgor
What are the early changes in cells in injury? (Reversible and irreversible)
1.swelling of cell and organelles
2.blebbing of plasma membrane
3.detachement of ribosomes from ER
4. Chromatin clumping
What are vacuoles?
Pinched off segments of ER
What colour does eosinophils take when dyed with H&E dye during cell death?
Red
Why no blue dye seen with H&E during cell death?
RNA binds haematoxylin blue - RNA is lost in cell death
What are ‘myelin figures’?
Phospholipid aggregates from destroyed lipid membranes - seen in cell injury
What are the ultrastructural changes that can be seen in cell injury (5)
1.plasma membrane alterations eg blebbing, blunting, loss of microvilli
2.mitochondrial changes: swelling and appearance of small densities
3.myelin figures
4.Dilatation of ER
5.nuclear alterations
What are the characteristics of necrosis (4)
1.denaturation proteins
2.leakage contents through damaged cell membrane
3.enzymatic digestion
4.local inflammation
Necrosis: what are the possible patterns of nuclear change? 3
- Karyolysis: basophilia within chromatin fading
- Pyknosis: nuclear shrinkage, increased basophilia
3.karyorrhexis: pyknotic nuclear fragmentation (happens after pyknosis)
What are the characteristics of irreversible injury? 2
- Mitochondrial dysfunction
- Cell membrane dysfunction
What are the characteristics of mitochondrial dysfunction in irreversible cell injury?
1.Loss of oxidative phosphorylation
2. Loss of ATP generation
Example of Liquefactive necrosis?
Bacterial/fungal infection into tissues
What is Liquefactive Necrosis?
Cell death and gets digested to form a liquid (accumulation of leukocytes)