General Patho Flashcards
Name the tissues which cannot undergo hyperplasia.
Skeletal muscle, cardiac muscle, nerves
What is an example of physiologic hyperplasia?
Endometrial hyperplasia in pregnancy
What is an example of pathologic hyperplasia (that will not increase risk of ___ cancer)?
Benign Prostatic Hyperplasia will not increase risk of prostate cancer)
Hypertrophy is…
increase in cell size
Involution is…
decrease in cell number
Atrophy is…
decrease in cell size
Name two examples of metaplasia.
Barret oesophagus: gastric reflux changes oesophageal lining from NKSSE to columnar epithelium
Smoking: smoking changes respiratory columnar epithelium to squamous epithelium, which can cause squamous cell carcinoma
Name the 4 causes of cell injury
Hypoxia, trauma, nutrient deficiencies or excess, mutations
Name the causes of Hypoxia
Ischaemia, Hypoxemia, Decreased O2 carrying capacity
Describe swelling as a consequence of cell injury
• reversible
• due to low ATP causing Na+ K+ pump dysfunction
• leads to cell swelling
• swelling RER causes ribosomes to drop off, leading to decreased protein synthesis
Describe membrane damage as a consequence of cell injury
• irreversible
• plasma membrane damage causes cytosolic enzymes to leak into blood
• mitochondrial membrane damage causes cytochrome C to leak into cell, activating capsases to cause apoptosis
• lysosomal membrane damage causes hydrolytic enzymes to leak into cell, causing autolysis
leads to cell death
Name the 3 types of cell death
Autolysis (during organism death), Apoptosis (programmed cell death), Necrosis (pathological cell death due to injury)
Name the 3 types of nucleus loss associated with cell death
- Pyknosis: nucleus condensation
- Karyorrhexis: nuclear fragmentation
- Karyolysis: nuclear dissolution
How are caspases activated in apoptosis?
Cell injury + DNA damage lead to:
1. inactivated bcl2 in mitochondrial membrane –> cytochrome C leaked from mitochondria to cytoplasm
2. FASL binding to FAS on target cell
3. CD8 CTL granzymes entering the cell (via perforins)
How do capsases cause apoptosis?
• activate proteases, causing cytoskeleton breakdown and cell shrinkage
• activate endonucleases, causing DNA breakdown and nucleus disappearance
Name the 7 types of necrosis
- Coagulative
- Hemorrhagic
- Liquefactive
- Suppurative
- Caseous
- Fat
- Fibrinoid
Describe the features of coagulative necrosis.
• firm dead tissue with cell shape retained
• seen in ischaemic infarctions due to obstructed arterial supply (except the brain)
• gross appearance: wedge shaped and pale
gangrenous necrosis is extensive coagulative necrosis without liquefactive necrosis, causing gross black appearance
Describe the features of liquefactive necrosis.
• enzymatic lysis of cells causes liquefaction
• seen in brain infarcts, due to proteolytic enzymes from microglial cells
• seen in pancreatic infarcts, due to pancreatic proteases liquefying parenchyma
Describe the features of suppurative necrosis.
• liquefactive necrosis in abcesses or empymas
• caused by neutrophils releasing proteolytic enzymes to liquefy tissue
Describe the features of caseous necrosis.
• cheese like appearance, soft and friable
• combination of liquefactive and coagulative necrosis
• seen in granulomatous inflammation from TB or fungal infections
Describe the features of fat necrosis.
• chalky white appearance due to calcium deposition
• seen in trauma to fat and necrosis of fat-surrounding organs
• seen in acute pancreatitis as pancreatic lipases breakdown surrounding fat
Describe the features of fibrinoid necrosis
• necrosis of blood vessel wall
• fibrin leakage results in visible strings of fibrin
• seen in vasculitis
Describe the features of haemorrhagic necrosis.
• “red infarction”: appears red
• type of coagulative necrosis
• in organs with dual blood supply + infarcts due to obstructed venous outflow
• seen in testicular torsion: blood vessels twist on itself, artery does not collapse due to thick walls but veins collapse
