Ch 1 Pathoma Flashcards
Hypertrophy
an increase in size of cells
Hyperplasia
an increase in number of cells (production of new cells form stem cells)
_______ involves gene activation, protein synthesis, and production of organelles
Hypertrophy
Permanent tissues such as these 3, cannot make new cells and can only hypertrophy
Cardiac muscle, skeletal muscle, and nerve
An exception to pathologic hyperplasia progressing to dysplasia and eventually cancer
Benign prostatic hyperplasia (BPH) - does not increase risk for prostate cancer
_____ occurs via a decrease in size and number of cells
Atrophy
Decrease in cell number occurs via ______. And decrease in size occurs via ______ and ______
Apoptosis; Ubiquitin proteosome degradation of the cytoskeleton; Autophagy
Metaplasia
A change in stress on an organ leads to a change in cell type (most commonly involves surface epithelium) - metaplastic cells are better able to handle new stress
Barrett’s Esophagus
normal esophagus is lined by nonkeratinizing squamous epithelium –> acid reflux causes metaplasia to non-ciliated mucin-producing columnar cells
Metaplasia and dysplasia are both (reversible/irreversible)
Reversible with removal of driving stressor - if stress persists can become irreversible (carcinoma) - apocrine metaplasia of breast carries no increased risk for cancer
Vitamin A deficiency can result in _____
Metaplasia
______ is necessary for differentiation of specialized epithelial surfaces such as the conjuctiva covering the eye
Vitamin A - in deficiency, conjuctiva can undergo metaplasia into keratinizing squamous epithelium
Keratomalacia
destruction of the cornea due to vitamin A deficiency induced metaplasia of the conjuctiva
Example of mesenchymal (connective) tissue metaplasia
Myositis Ossificans - CT w/in muscle changes to bone during healing after trauma
Dysplasia
disordered cellular growth (ex: cervical intraepithelial neoplasia CIN) - often a precursor to cancer - often arises from longstanding hyperplasia (endometrial hyperplasia) or metaplasia (Barrett’s esophagus)
Aplasia and Hypoplasia
failure of cell production during embryogenesis (unilateral renal agenesis) and decrease in cell production during embryogenesis (streak ovary in Turner syndrome)
______ occurs when a stress exceeds the cell’s ability to adapt
cellular injury - likelihood depends on type of stress, severity, and type of cell affected; slowly developing ischemia results in atrophy and acute ischemia results in injury
5 common causes of cellular injury
inflammation, nutritional deficiency/excess, hypoxia, trauma, genetic mutations
3 causes of hypoxia
ischemia (decreased blood flow through an organ), hypoxemia (low partial pressure of O2 in blood), decreased O2-carrying capacity of blood
3 causes of ischemia
decreased arterial perfusion (atherosclerosis), decreased venous drainage (Budd-Chiari syndrome), shock (generalized hypotension –> poor tissue perfusion)
4 causes of hypoxemia (low partial pressure of O2 in blood)
high altitude (decreased PAO2), hypoventilation (decreased PAO2), diffusion defect (normal PAO2 - ex: fibrosis), V/Q mismatch (right to left shunt or alveolar dead space)
3 causes of decreased O2 carrying capacity (normal PaO2)
Anemia (normal SaO2), CO poisoning (decreased SaO2), methemglobinemia (decreased SaO2)
Classic finding of CO poisoning and methemglobinemia (and tx)
cherry red appearance of skin (early sign of exposure is headache); cyanosis with chocolate-colored blood (tx is intravenous methylene blue which helps reduce Fe3+ back to Fe2+ –> Fe2 binds O2) - seen with oxidant stress (sulfa and nitrate drugs) or in newborns
Low ATP disrupts these 3 key cellular functions
Na/K pump (leads to Na buildup and water buildup/swelling), Ca2+ pump (results in Ca buildup in cytosol which can lead to enzyme activation), aerobic glycolysis (leads to anaerobic glycolysis, increasing lactic acid and lower pH –> denatures proteins and precipitates DNA)
The hallmark of reversible injury is _______
cellular swelling - results in loss of microvilli and membrane blabbing, and dissociation of ribosomes (RER swelling) and decreased protein synthesis
The hallmark of irreversible injury is _______
membrane damage - results in cytosolic enzymes leaking in to serum (cardiac troponins), additional Ca entering cell, mitochondrial membrane damage results in loss of ETC chain and leakage of cytochrome c causing apoptosis; lysosome membrane damage results in hydrolytic enzymes leaking (further activated by additional Ca in cell)
Morphologic hallmark of cell death is ______ and the three phases this occurs.
Loss of the nucleus; occurs via nuclear condensation (pyknosis), fragmentation (karyorrhexis), and dissolution (karyolysis)
Two mechanisms of cell death
necrosis (murder) and apoptosis (suicide)
Necrosis and the 6 types
death of large groups of cells followed by acute inflammation. Due to some underlying pathologic process (never physiologic). Coagulative, liquefactive, gangrenous, caseous, fat, and fibrinoid
In _____ necrosis, the tissue remains firm and cell shape and organ structure are preserved by _______ of proteins, but the nucleus disappears
coagulative; coagulation
Characteristic of ischemic infarction of any organ except the brain
In ______ necrosis, area of infarcted tissue is often wedge-shaped and pale
coagulative; wedge points to focus of vascular occlusion; red infarct occurs when blood re-enters loosely organized tissue (seen in organs with dual blood supply)
Liquefactive necrosis is characteristic of these three instances
brain infarction (proteolytic enz from microglial cells liquefy the brain), abscess (prot enz from neutrophils liquefy tissue), pancreatitis (prot enz from pancreas liquefy parenchyma)
Gangrenous necrosis is characteristic of
ischemia of lower limb (and GI tract) - dry gangrene resembles mummified tissue; wet if superimposed infection of dead tissue occurs
_____ necrosis is soft and friable necrotic tissue with cottage cheese like appearance
Caseous - combination of coagulative and liquefactive (soup like)
Caseous necrosis is characteristic of
granulomatous inflammation due to TB or fungal infection
Fat necrosis appearance
necrotic adipose tissue with chalky white appearance due to deposition of calcium
Fat necrosis is characteristic of
trauma to fat (e.g. breast) and pancreatitis-mediated damage of peripancreatic fat; fatty acids released by trauma or lipase (pancreatitis) join with calcium via saponification
Saponification can occur via dystrophic calcification or metastatic calcification - what’s the difference?
DC occurs when calcium deposits on dead tissues in the setting of normal serum calcium and phosphate. MC occurs when high serum calcium or phosphate levels lead to calcium deposition on normal tissues (ex: hyperparathyroidism leading to nephrocalcinosis)
Fibrinoid necrosis is characteristic of
and appearance
malignant hypertension and vasculitis; it causes necrotic damage to bv wall - leaking of proteins (including fibrin) into vessel wall results in bright pink staining of wall microscopically
Three major examples of apoptosis
endometrial shedding during period, removal of cells during embryogenesis (de-webbing), CD8+ T cell mediated killing of virally infected cells
Apoptosis morphology
dying cell shrinks (cytoplasm becomes more eosinophilic since it’s more concentrated), nucleus condenses and fragments, apoptotic bodies fall from the cell and are removed by macrophages - NOT followed by inflammation
Apoptosis is mediated by ___ that activate ____ and ____
caspases; proteases (break down cytoskeleton) and endonucleases (break down DNA)
3 pathways by which caspases are activated
intrinsic mitochondrial pathway (injury, dan damage, or dec hormonal stim leads to inactivation of Bcl2 which allows cytochrome c to leak), extrinsic receptor-ligand pathway (FAS ligand binds FAS death receptor on target cell - negative selection of thymocytes in thymus), cytotoxic CD8+ T cell mediated pathway (perforin secreted by t cells create pores in membrane and releases granzyme through pores to activate caspase)
