Patho - FA 206 - 219 Flashcards
Barrett esophagus is an ex. of what type of cellular injury? What is it?
metaplasia - replacement of one cell type with another. Barrett - respiratory ciliated columnar epith with stratified squamous epith
Barrett esophagus can lead to what type of neoplasia?
Esophageal adenocarcinoma
Dysplastic changes ex?
loss of uniformity of cell size and shape (pleomorphism); loss of tissue orientation; nuclear changes (eg, inc nuclear:cytoplasmic ratio and clumped chromatin).
Reversible cell injury
Dec ATP –> mitoch swelling Ribosomal/polysomal detachment Plasma membrane changes (eg, blebbing) Nuclear changes (eg, chromatin clumping) rapid loss of fxn
Irreversible cell injury
Breakdown of plasma membrane Mitochondrial damage/dysfunction Rupture of lysosomes Nuclear degradation
Process of Nuclear Degradation
= pyknosis (nuclear condensation) –> karyorrhexis (nuclear fragmentation caused by endonuclease-mediated cleavage) –> karyolysis (nuclear dissolution)
How is the cell membrane affected in apoptosis vs necrosis?
In apoptosis, Cell membrane typically remains intact without significant inflammation (unlike necrosis).
Signs of apoptosis cellularly? (histologically)
Characterized by deeply eosinophilic cytoplasm and basophilic nucleus, pyknosis, and karyorrhexis.
Indicator of apoptosis?
DNA laddering (fragments in multiples of 180 bp
Name 2 pro and 2 anti apoptotic proteins in the Bcl 2 family
Pro - BAX BAK Anti - Bcl-2 Bcl-XL
How do BAX/BAK inititate apoptosis?
BAX and BAK form pores in the mitochondrial membrane –> release of cytochrome C from inner mitochondrial membrane into the cytoplasm –> activation of caspases.
How does Bcl-2 (-) apoptosis?
Bcl-2 keeps the mitochondrial membrane impermeable, thereby preventing cytochrome C release.
Disease assoc with Bcl-2? What genetic defect?
follicular lymphoma; t(14,18)
List the 2 pathways of extrinsic death via ligand?
Ligand receptor interactions (FasL binding to Fas [CD95] or TNF-α binding to its receptor) Immune cell (cytotoxic T-cell release of perforin and granzyme B)
Which pathway of cell death is used in the thymus to filter out non-functional lymphocytes?
Fas-FasL interaction is necessary in thymic medullary negative selection.
Disease caused by defect Fas/Fas-L interactions?
autoimmune lymphoproliferative syndrome
Ischemia/infarcts cause coagulative necrosis everywhere except? what type of necrosis there?
in the brain, where u have liquefactive necrosis
How does liquefactive necrosis occur?
Neutrophils release lysosomal enzymes that digest the tissue
Histo signs of liquefactive necrosis?
Early: cellular debris and macrophages Late: cystic spaces and cavitation (brain)
Define granuloma
Focus of epithelioid cells (activated macrophages with abundant pink cytoplasm) surrounded by lymphocytes and multinucleated giant cells (formed by fusion of several activated macrophages).
Which infections lead to caseous necrosis?
TB, systemic fungi (eg, Histoplasma capsulatum), Nocardia
two types of fat necrosis?
Enzymatic: acute pancreatitis (saponification of peripancreatic fat) Nonenzymatic: traumatic (eg, injury to breast tissue)
Why does fat necrosis have a chalk like appearence?
free fatty acids from fat breakdown will bind calcium (saponification)
What type of hypersensitivity reaction leads to fibrinoid necrosis?
HS-III
Another cause of fibrinoid necrosis?
Plasma protein leakage from damaged vessel
Differences between wet and dry gangrene?
Dry - ischemic, coagulative necrosis Wet - superinfection, liquefactive superimposed on coagulative
Region most vulnerable to infarct - brain?
ACA/MCA/PCA boundary areas
Region most vulnerable to infarct - heart?
Subendocardium
Region most vulnerable to infarct - kidney?
Straight segment of proximal tubule (medulla) Thick ascending limb (medulla)
Region most vulnerable to infarct - liver?
Area around central vein (zone III)
Region most vulnerable to infarct - colon?
Splenic flexure, rectum
Neurons most vulnerable to hypoxemia/ischemia?
Purkinje cells of the cerebellum and pyramidal cells of the hippocampus and neocortex (zones 3, 5, 6).
red infarcts are seen where?
- Occurs in venous occlusion and tissues with multiple blood supplies (eg, liver, lung A, intestine, testes) 2. w/ reperfusion (eg, after angioplasty). Red = reperfusion
3 enzymes that fight free radicals?
catalase, superoxide dismutase, glutathione peroxidase
3 vitamins that fight free radicals (antioxidants)?
Vitamins A,C,E
3 examples of oxygen toxicity leading to free radical injury?
retinopathy of prematurity (abnormal vascularization), bronchopulmonary dysplasia, reperfusion injury after thrombolytic therapy
2 drugs that lead to free radical injury?
acetaminophen OD, carbon tetrachloride
Mech of carbon tetrachloride injury?
converted by cytochrome P-450 into CCl3 free radical–> fatty liver & centrilobular necrosis
Where is carbon tetrachloride used (bonus)?
Dry cleaning, refrigerants, lava lamps, used to be used in fire extinguishers
How do calcium deposits look on H&E?
deeply basophilic