Pathology - First Aid Flashcards
Apoptosis requires…
ATP.
Both the intrinsic and extrinsic pathways for apoptosis activate…
cytosolic caspases that mediate cellular breakdown.
Unlike necrosis, apoptosis does not have…
significant inflammation.
Apoptosis is charachterized by..
deeply eosinophilic cytoplasm, cell shrinkage, nuclear shrinkage (pyknosis) and basophilia, membrane blebbing nuclear fragmentation (karyorrhexis), and formation of apoptotic bodies, which are then phagocytosed.
DNA laddering is a…
sensitive indicator of apoptosis.
Durrying karyorrheix, endonucleases will…
cleave at internucleosomal regions, yielding 180-bp fragments.
Radiation therapy causes…
apoptosis of tumors and surrounding tissue via free radical formation and dsDNA breakage.
Intrinsic apoptosis pathway is invovled in..
tissue remodeling in embryogenesis.
Intrinsic pathway occurs when…
a regulating factor is withdrawn from a proliferating cell population (ex. decreased IL-2 after a completeed immunological rxn leads to apoptosis of proliferating effector cells).
Intrinsic pathway also occurs after exposure to…
injurious stimuli (radiation, toxins, hypoxia).
During the intrinsic pathway, changes in proportions of…
anti- and pro- apoptotic factors lead to increased mitochondrial permeability and cytochrome c release.
BAX and BAK are…
pro-apoptotic proteins.
Bcl-2 is…
anti-apoptotic.
Bcl-2 prevents…
cytochrome c release by binding to and inhibiting Apaf-1.
Apaf-1 normally…
induces the activation of caspases.
If Bcl-2 is overexpressed, then…
Apaf-1 is overly inhibitedd, leading to decreased caspase activation and tumorigenesis.
2 pathways of the extrinsic apoptosis pathway
- ligand receptor interactions (FasL binding to Fas)
2. immune cell (cytotoxic T-cell release of perforin and granzyme B)
Fas-FasL interaction is necessary in…
thymic medullary negative selection.
Mutations in Fas incnresae…
numbers of circulating self-reacting lymphocytes due to failure of clonal deletion.
After Fas crosslinks with FasL…
multiple Fas molecules coalesce forming a binding site for a death domain-containing adapter protein, FADD.
FADD binds…
inactive caspases, activating them.
Defective Fas-FasL interaction is the basis for…
autoimmune disorders.
Coagulative Necrosis
- heart, liver, kidney
- occurs in tissues supplied by end-arteries
- increased cytoplasmic binding of acidophilic dye
- proteins denature first, followed by enzymatic degradation
Liquefactive Necrosis
- brain, bacterial abscess
- occurs in CNS due to high fat content
- enzymatic degradation is due to the release of lysosomal enzymes
Caseous necrosis
-TB, systemic fungi, nocardia
Fatty necrosis
-enzymatic (pancreatitis (saponification)) and nonenzymatic (breast trauma); calcium deposits appear dark blue on staining
Fibrinoid necrosis
- vasculitides (Henoch-Schonlein purpura)
- Churg-Strauss
- malignant HTN
- amorphous and pink
Gangrenous necrosis
- dry (ischemi coagulative) and wet (infxn)
- common in limbs and GI tract
Reversible cell injury (w/ O2)
- ATP depletion
- cellular/mitochondrial swelling
- nuclear chromatin clumping
- decreased glycogen
- fatty change
- ribosomal/polysomal detachment
- membrane blebbing
Irreversible cell injury
- nuclear pyknosis, karyorrhexis, karyolysis
- plasma membrane damage
- lysosomal rupture
- mitochondrial permeability/vacuolization
Heart areas susceptible to ischemia/hypoxia
subendocardium (LV)
Kidney areas susceptible to hypoxia/ischemia
straight segment of proximal tubule (medulla)
thick ascending limb (medulla)
Liver area susceptible to hypoxia/ischemia
area around central vein (zone III)
Colon areas susceptible to hypoxia/ischemia
splenic flexure, rectum
Reperfusion injury is due to…
damage by free radicals.
Red infarcts occur in…
loose tissues with multiple blood supplies such as liver, lungs and intestine.
Pale infarcts occur in…
solid tissues with a single blood supply such as heart, kidney and spleen.
First sign of shock is…
tachycardia.
Shock in the setting of DIC secondary to trauma is likely due to…
sepsis.
Distributive shock includes…
septic, neurogenic, and anaphylactic shock.
Features of Distributive shock
- high-output failure (decreased TPR, increased CO, increased venous return)
- decreased PCWP
- vasodilation (warm, dry skin)
- failure to increase blood pressure with IV fluids
Features of hypovolemic/cardiogenic shock
- low-output failure (increased TPR, decreased CO, decreased venous return)
- PCWP increased in cardiogenic; decreased in hypovolemic
- vasoconstriction
- blood pressure restored with IV fluids
Inflammation is characterized by…
redness, pain, heat, swelling and loss of function.
Vascular component of inflammation
increased vascular permeability, vasodilation, endothelial injury
Cellular component of inflammation
neutrophils extravasate from circulation to injured tissue to participate in inflammation through phagocytosis, degranulation and inflammatory mediator release
Acute inflammation is mediated by…
neutrophils, eosinophils, and antibodies. There i rapid onset and it lasts minutes to days.
Outcomes of acute inflammation include…
complete resolution, abscess formation, and progression to chronic inflammation.
Chronic inflammation is mediated by…
mononuclear cell and fibroblasts. Characterized by persistent destruction and repair.
Chronic inflammation is associated with…
blood vessel proliferation and fibrosis.
A granuloma is a…
nodular collection of epithelioid macrophages and giant cells.
Outcomes of chronic inflammation include…
scarring and amyloidosis.
Chromatolysis is a process involving…
the cell body following axonal injury. Changes reflect increased protein synthesis in an effort to repair the damaged axon.
Chromatolysis is characterized by (3):
- round cellular swelling
- displacement of the nucleus to the periphery
- dispersion of Nissl substance throughout the cytoplas
Dystrophic calcification is…
calcium deposition in tissues secondary to necrosis.
Dystrophic calcification tends to be…
localized (ex. on heart valves).
Dystrophic calcification is seen in…
TB (lungs and pericardium), liquefactive necrosis of chronic abscesses, fat necrosis, infarcts, throbmi, schistosomiasis, Monckeberg arteriolosclerossi, congenital CMV + toxoplasmosis and psammoma bodies.
Dystrophic calcification is not directly associated with…
hypercalcemia. Patients are usually normocalcemic.
Metastatic calcification is..
widespread deposition of calcium in normal tissue secondary to hypercalcemia or high calcium-phosphate product. Pts are not normocalcemic.
In metastatic calcification, calcium deposits predominantly are in…
interstitial tissues of kidney, lungs and gastric mucosa (bc these tissues lose acid quickly; increased pH favors deposition).
Causes of hypercalcemia leading to metastatic calcification include…
primary hyperparathyroidism, sarcoidosis, hypervitaminosis D.
Causes of high calcium-phoshpate product leading to metastatic calcification include…
chronic renal failure + secondary hyperparathyroidism, long-term dialysis, calciphylaxis and warfarin.
4 Steps of Leukocyte Extravasation
- Margination and rolling
- Tight-binding
- Diapedesis (leukocyte travels between endothelial cells and exits the blood vessels)
- Migration (leukocyte travels through interstitium to site of injury or infection guided by chemotactic signals)
Step 1 Mediators
Vasculature: E-selectin, P-selectin, glyCAM-1, CD34
Leukocyte: Sialyl-Lewis, L-selectin
Step 2 mediators
Vasculature: ICAM-1, VCAM-1
Leukocyte: CD11/18, VLA-4 integrin
Step 3 mediators
Vasculature: PECAM-1
Leukocyte: PECAM-1
Step 4 mediators
Vasculature: C5a, IL-8, LTB4, kallikrein, PAF (chemotactic products released in response to bacteria)
Free radicals damage cells via…
membrane lipid peroxidation, protein modification and DNA breakage.
Free radical injury is initiated via…
radiation exposure, drug metabolism, redox rxns, NO, transition metals, and leukocyte oxidative burst.
Free radicals can be elimitated by…
enzymes (catalase, SOD, glutathione, and peroxidase)
spontaneous decay
antioxidants (Vit A, C, E)
Pathologies of Free Radicals include:
- retinopathy of prematurity
- bronchopumonary dysplasia
- carbon tetrachloride (leading to liver necrosis)
- acetaminophen overdose
- iron overload
- reperfusion injury
Inhalation injury is the most common…
pulmonary complication after exposure to fire. INhalation of the products of combustion (carbon, toxic fumes) leads to chemical tracheobronchitis, edema and pneumonia.
Hypertrophic scars features
- increased collagen synthesis
- parallel collagen
- confined to borders of original wounds
- infrequently recur following resection
Keloid scars features
- extremely increased collagen
- disorganized collagen
- extneds beyond borders of original wound
- frequently recurs following resection
PDGF is secreted by…
activated platelets and macrophages. It induces vascular remodeling and smooth muscle cell migration. It stimulates fibroblast growth for collagen synthesis.
FGF stimulates…
all aspects of angiogenesis.
EGF stimulates…
cell growth via tyrosine kinases
TGF-beta has a role in…
angiogenesis, fibrosis, cell cycle arrest.
Metalloproteinases have a role in…
tissue remodeling.
Inflammatory stage of wound healing mediators
platelets, neutrophils, macrophages
Characteristics of the inflammatory stage of wound healing
- clot formation
- increased vessel permeability
- neutrophil migration
- maacrophages clear debris 2 days later
Proliferative stage of wound healing (2-3 days later) mediators
fibroblasts, myofibroblasts, endothelial cells, keratinocytes, macrophages
Characteristics of the proliferative stage of wound healing
- deposition of granulation tissue and collagen
- angiogenesis
- epithelial cell proliferation
- dissolution of clot
- wound contraction (mediated by myofibroblasts)