Cell Pathology Flashcards
Concentric hypertrophy
Sarcomeres proliferate in parallel
Pressure overload on the heart, such as with hypertension or aortic stenosis results in concentric hypertrophy - increases the thickness of the left ventricular wall
Eccentric hypertrophy
Sarcomeres proliferate in series
Volume overload on the heart, such as with aortic regurgitation, results in eccentric hypertrophy - dilate the lumen of the left ventricle
What cellular change results in hypertrophy
Increased cellular protein production from the action of growth factors
Atrophy
May result from decreased blood supply
Other causes: disuse, denervation, endocrine insufficiencies
Atrophy results from decreased protein synthesis and increased protein degradation in cells, which occurs mainly by the ubiquitin-proteasome pathway. Ubiquitin is a protein-tag that marks proteins to be destroyed within proteasomes. This pathway is thought to be responsible for atrophy seen in a variety of catabolic conditions, such as cancer cachexia (starvation).
Brain with grossly seen small gyri with enlarged sulci
Atrophy
Renal atrophy
Can be caused by renal artery stenosis (also a cause of secondary hypertension due to the increased secretion of renin increasing aldosterone secretion)
What cell lines do not undergo hyperplasia?
Permanent cells: muscle and nerve
Pathologic hyperplasia
Examples
Compensatory pathologic hyperplasia: regenerating liver, increased erythrocyte #’s in response to chronic hypoxia, and increased B lymphocytes within nodes in response to infection (follicular hyperplasia).
Note that liver tissue has an amazing ability to regenerate after resection or trauma through replication of remaining hepatocytes from progenitor cells. Histology will show normal hepatic tissue.
Purely pathologic hyperplasia
Examples
Abnormal enlargement of the endometrium (endometrial hyperplasia due to excess estrogen unopposed by progesterone) or the prostate (increase in # of glandular epithelial and stromal cells)
Hypoplasia
Examples
Hypogonadism
Turner syndrome (streak ovaries)
Klinefelter syndrome (small testes)
Aplasia
Failure of cell production, usually due to a failure of multipotential stem cells.
Aplastic anemia - failure of multipotential stem cells (histology of aplastic bone marrow shows mainly fat with very few cells)
Metaplasia
Reversible, non-neoplastic replacement of one normal cell type by another normal type.
Examples of metaplasia that result from chronic inflammation:
- Resp. epithelium changing to stratified squamos epithelium (sqaumos metaplasia)
- Normal glandular epithelium of the endocervix changing to stratified sqtype mucosa squamous epithelium (squamous metaplasia)
- Normal stratified squamous epithelium of the lower esophagus changing to intestinal-type mucosa (Barrett esophagus) in response to gastroesophageal chronic reflux
- The normal transitional epithelium of the urinary bladder changing to squamous epithelium (squamous metaplasia) - such as with Schistosoma infection
Myositis ossificans
Metaplasia in which a hard mass develops within skeletal muscle after trauma with hemorrahge that duoes not go away (osseous metaplasia)
Keratomalacia
Squamous metaplasia of the conjunctiva - may result from vit A deficiency
Necros is _____
Passive or physiologic process
Necrosis is always a passive process and never a physiologic process
Dysplasia
Premalignant - refers to disorganized cell growth characterized by the presence of atypical or dyplastic cells
In contrast to cancer - dysplasia is characterized by reversibility of changes
Coagulative necrosis
Characterized by coagulation of cellular proteins and preservation of cellular architecture with acidophilic (red/pink color) change of the cytoplasm (due to increased cytoplasmic binding to the eosin stain) and either without cell nuclei or with nuclei still undergoing karyolysis
Usually occurs as a result of ischemia or infarction involving solid organs (such as the heart - myocardial infarct), kidneys, liver, or spleen (NOT THE BRAIN)
Liquefactive necrosis
Necrotic tissue becomes liquefied - results from hydrolytic enzyme-induced tissue digestion from numerous lysosomal enzymes being released from numerous inflammatory cells being present (usually neutrophils)
Classically results from pyrogenic bacterial infections, which caus and acute inflammatory response with influx of numerous neutrophils.
Liquefactive necrosis is the type of necrosis that is produced with ischemic necrosis of the brain since numerous microlgia are present
Gangrenous necrosis
Usually occurs in the extremities or GI tract - occurs secondary to severe ischemia and resuls in a combination of coagulative and liquefactive necrosis
Dry gangrene - coagulative pattern predominates
Wet gangrene - liquefactive pattern predominates (due to superimposed bacterial infection)
Caseous necrosis
Combination of coagulative and liquefactive necrosis, but the necrotic cells are not totally dissolved and remain as amorphic, coarsely granular, eosinophilic debris.
Grossly has the appearance of clumped cheese - classically seen with tuberculous infections.
Histologic section will reveal caseating granulomas, which are composed of an aggregate of activated macrophages (ganuloma) with the center having the amorphic granular debris. This central area of caseous necrosis is absent from non-caseating granulomas.