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Year 2 Semester 2 > Pathology > Flashcards

Flashcards in Pathology Deck (311)
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271

What is meant by metaplasia?

Reversible change-replacement of one adult cell type by another
Due to reprogramming of stem cells

272

What are chaperones?

Interact with proteins, aid proper folding, transport and degradation of proteins

273

What is haemosiderin a storage form of?

Iron
In tissues, ferritin is transferred to haemosiderin granules

274

What are the causes of jaundice?

Excessive haemolysis
Severe hepatic injury
Obstructed bile flow

275

What is hypercalcaemia seen with?

Increased PTH secretion
Destruction of bone tissue
Vitamin D intoxication
Renal failure (secondary hyperparathyroidism)

276

What is an amyloid?

A pathological proteinaceous substance deposited between cells

277

What factors cause cell injury?

Decreased O2 availability
Infectious agents
Immunological dysfunctions
Chemicals and toxins
Physical agents (trauma, temperature, pH, radiation)
Nutritional deficiencies
Genetic derangement (specific enzyme derangement)

278

What are the effects of oxygen free radicals in cell injury?

DNA fragmentation
Protein cross-linking and fragmentation
Membrane lipid peroxidation

279

Which enzymes are activated by increased intracellular Ca2+?
What are the consequences?

ATPase: decreased ATP
Phospholipase: decreased phospholipids
Endonuclease: nuclear chromatin damage
Protease: disruption of membrane and cytoskeletal proteins

280

Give 4 potential causes of cell membrane damage that lead to irreversible injury

Progressive loss of membrane phospholipids due to activation of phospholipase by Ca2+
Cytoskeletal abnormalities due to activation of proteases and cell swelling
Toxic oxygen radicals after restoration of blood flow
Lipid breakdown products from phospholipid degradation
ULTIMATELY A MASSIVE INFLUX OF CALCIUM

281

What is the difference between apoptosis and necrosis?

Apoptosis= programmed cell death. Phagocytosis of apoptotic cells and fragments. No inflammation. Cells shrink. Plasma membrane stays intact. Cellular contents stay intact.
Necrosis= enzymatic digestion and leakage of cellular contents. Cells swell. Plasma membrane is disrupted. Cellular contents undergo enzymatic digestion.

282

What are the 4 types of necrosis?

Coagulative necrosis: Hypoxic cell death, preservation of cell outline
Liquefactive necrosis: Enzymatic digestion, complete digestion of cells -> liquid mass
Caseous necrosis: Complete obliteration of tissue architecture, surrounded by inflammatory cell border
Fat necrosis: focal destruction of adipose tissue, released fatty acids combine with calcium

283

Describe the morphology of apoptosis

1) Cell shrinkage
2) Chromatin condensation
3) Formation of cytoplasmic blebs and apoptotic bodies
4) Phagocytosis of apoptotic cells (by adjacent parenchymal cells and/or macrophages)

284

Why do neurones have to die in an apoptotic way?

We don't want inflammation of neurones in the brain. Instead they shrink and microglia quickly remove them.

285

Platelets adhere to endothelium via what?

GPI to vWF or collagen

286

Platelets aggregate with other platelets via what?

GPIIb/IIa through fibrinogen or vWF bridges

287

Platelets can release what after activation?

Thromboxan, serotonin, factor V, ADP, ATP and plasminogen

288

Name some platelet agonists

PAF, collage, ADP, thrombin

289

What are vWF and P-selectin produced by?

Endothelial cells

290

Define secondary haemostasis

Formation of the fibrin clot

291

What are the 2 products of the coagulation cascade?

Thrombin (factor IIa) and insoluble fibrin

292

The steps of the coagulation cascade are carried out in the presence of what?

Calcium

293

Which is the only factor involved in the extrinsic pathway of the coagulation cascade?

VII

294

What is the intrinsic pathway activated by?

Intravascular causes- exposed damaged endothelium

295

What is the extrinsic pathway activated by?

Tissue factor released from damaged tissue

296

Which factor (combined with free calcium ions) causes cross-linking of fibrin?

XIIIa

297

Which coagulation factors are vitamin-K dependant?

II, VII, IX, X
(2, 7, 9, 10)

298

Which coagulation factors are in the contact group?

XI, XII
(11 and 12)

299

Which coagulation factors are in the highly labile fibrinogen group?

I, V, VIII, XIII
(1, 5, 8, 13)

300

What is the preferred anticoagulant? Why?

Citrate as it forms an ionic bond with calcium that new added calcium can override