Cellular Adaptation and Cell Necrosis Flashcards
Cell Adaptation
prolonged exposure of cells to adverse or exaggerated normal stimuli
evokes various changes at the level of individual cells, tissues or whole organs
cause removed
- most cells revert to normalcy
- some do not –> detrimental results
How Cells Adapt to Change (6)
Atrophy Hypertrophy Hyperplasia Metaplasia Dysplasia Anaplasia
Atrophy: definition
Decrease in size of a tissue, organ or entire body
physiologic or pathologic
Atrophy: physiologic
thymus undergoing involution
ovaries, uterus and breasts after menopause
atrophic bones and muscles in the elderly become thin and prone to fracture
Atrophy: pathologic
ischemic organs are typically small (ie: kidneys involved with atherosclerosis)
- testicular atrophy
- alzheimer dementia
Hypertrophy: definition
an increase in the size of tissues or organs due to enlargement of individual cells
physiologic or pathologic
Hypertrophy: physiologic
enlargement of skeletal muscles in body builders due to weights
Hypertrophy: pathologic
heart adapts to increased workload
-concentric hypertrophy of L ventricular muscle mass (HT) is adaptive response to L ventricular pressure overload
Hyperplasia: definition
an adaptive increase in the number of cells that can cause enlargement of tissues or organs
Hyperplasia: pathologic
endometrial hyperplasia (due to estrogens)
hyperplastic polyps (of the colon or stomach)
hyperplastic prostate (BPH) - inc in size and number of glands and stroma
Hyperplasia: physiologic
hypertrophy of the uterine smooth muscle cells during pregnancy is accompanied by hyperplasia
Metaplasia: definition
an adaptive change of one cell type for another to suit the environment
reversible
can progress to dysplasia
Metaplasia: pathologic
squamous metaplasia of the bronchial epithelium due to smoking
gastric or glandular metaplasia of GE junction in Barrett Esophagus
Dysplasia: definition
disordered growth of tissues resulting from chronic irritation or infection
precancerous condition
Dysplasia: pathologic
detection of cervical dysplasia (cervical intraepithelial neoplasia) based on pap smears
Anaplasia: definition
undifferentiated and uncontrolled growth of cells
aka: malignancy, carcinoma, cancer, neoplasm
Anaplasia: pathologic
squamous cell carcinoma of the cervix
cancer of the lung
malignant melanoma
renal cell carcinoma
Anaplasia: microscopic hallmarks
- cellular pleomorphism
- irregular and hyperchromatic nuclei
- extremely high nuclear/cytoplasmic ratio
- large nucleoli
- large numbers of abnormal mitotic figures
Cell Necrosis: definition
the death of cells or groups of cells within a living organism
Cell Necrosis v. Autolysis
Necrosis: seen in the living (w/ inflammation)
Autolysis: seen after death
Types of Necrosis
coagulative
liquefactive
caseous
fat
Coagulative Necrosis: definition
most common form of necrosis
cell proteins are altered or denatured
cell outlines preserved
cytoplasm appears finely granular
Coagulative Necrosis
location: solid organs (heart, kidney, spleen, liver)
cause: anoxia
ie: heart tissue undergoing a myocardial infarction
Liquefactive Necrosis: definition
process by which dead cells liquify under the influence of certain cell enzymes
tissue becomes soft and gel-like
Liquefactive Necrosis
location: brain
ie:
- brain infarcts (stroke)
- bacterial infection - abscesses in the lungs/liver
Caseous Necrosis: definition
a form of coagulative necrosis in which a thick, yellowish, cheesy substance forms
Caseous Necrosis
location: tuberculosis
ie:
- Ghon complex (lung granulomas with caseous necrosis inside)
- some fungal infections (Histoplasmosis)
Fat Necrosis: definition
a specialized form of liquefaction necrosis caused by the action of lipolytic enzymes
Fat Necrosis
location: fat tissue (usually around pancreas, also breast)
rupture of pancreas –> enzymes released into fat tissue –> fat degradated into glycerol and FFA –> FFA binds with Ca –> soaps formed –> white calcified specks
Wet v. Dry Gangrene
Wet: inflammation and secondary liquefaction of coagulated tissue following bacterial infection
ie: advanced decubitus ulcers
Dry: necrotic tissue dries out - becomes black and mummified
Underlying infections contributing to gangrene…
infarction of the intestines or in a limb
atherosclerosis
diabetes
Dystrophic Calcifications: definition
macroscopic deposition of calcium in injured or dead tissues
represents an extracellular deposition of Ca from the circulation into dead or dying necrotic tissue
Dystrophic Calcifications: examples
- calcifications in atherosclerotic coronary arteries –> narrow vessels
- calcifications of mitral or aortic valves –> impeded blood flow (stenosis)
- calcification around breast cancers
- infant periventricular calcifications in congenital Toxoplasmosis
Metastatic Calcifications: definition
deranged calcium metabolism
associated with increased serum calcium levels
Metastatic Calcifications: examples
hyperparathyroidism
vitamin D toxicity
chronic renal failure
calcium stone formation in: -gallbladder -kidney -bladder (due to precipitation of salts from solution into tissues)
