W2/L11 Flashcards
(17 cards)
What are the principle mechanisms of cell injury? (4)
Damage to DNA & misfolding of proteins
Disturbance of calcium homeostasis
Damage to cell membranes
Mitochondria ATP depletion & ROS production
Why do cells swell in reversible injury?
Failure of the ATP-dependent pumps in plasma membrane
What happens in hepatocytes and myocardial cells when they’re reversibly injured?
Fat acuumulation
What are the nuclear changes from DNA breakdown?
Pyknosis
Karyorrhexis
Karyolysis
What happens in karyolysis
Complete dissolution of the nucleus with reduced basophilia (less purple)
What happens in pyknosis
The nucleus becomes small and intensely basophilic (purple)
What happens in karyorrhexis
Nuclear fragmentation
What colour is a necrotic cell?
Intensely eosinophilic
Why are necrotic cells more eosinophilic? (2)
Loss of ribosomal RNA
Increased eosin binding to damaged proteins
What is the histological feature of coagulative nectosis?
Ghost outlines
When does coagulative necrosis usually occur?
Infarction of solid organs (except brain)
Why does coagulative necrosis occur?
Slow enzymatic dissolution
What are the histological features of caseous necrosis?
Amorphous granular debris without distinct cell borders
When does caseous necrosis usually occur?
In necrotising granulomatous inflammation from TB
Where does liquefactive necrosis usually occur?
The brain
What pathology causes fat necrosis?
Acute pancreatitis causing release of lipases
What’s the result of fat necrosis?
Saponification (deposits of chalky white stuff) due to reaction of fatty acids with calcium
