what organs in the adult body do not proliferate its cells?
heart and brain
what is hypertrophy?
the increase in the size of each cell without proliferation
examples of physiologic hypertrophy
muscle hypertrophy due to exercise uterus hypertrophy from pregnancy
What induces uterus hypertrophy during pregnancy?
hormones
what can be observed in the uterus after menopause?
atrophy
example of pathological hypertrophy
increased workload on the heart due to hypertension. (hypertrophy of the cardiac muscle, especially the left ventricle)
what is brown atrophy of the heart?
the heart cells become thinner due to aging. lipofuscin accumulates and a dense number of nuclei will be visible (may look like hyperplasia)
what is hyperplasia?
the increase in proliferation or the number of cells in a tissue
physiological hyperplasia examples
hormone/growth factor-induced hyperplasia (proliferation of mammary glands during puberty) bone marrow proliferation in response to massive bleeding endometrium hyperplasia during menstrual cycle
examples of pathological hyperplasia
excessive release of hormones, leading to benign hyperplasia (prostate and endometrium) HPV-induced
2 symptoms caused by HPV
skin warts, mucosal lesion
what is atrophy?
reduction in the size OR number of cells
factors that contribute to atrophy
decreased workload, denervation (nerve damage), diminished blood supply, inadequate nutrition, loss of endocrine stimulation, pressure
what is metaplasia?
reversible changes in the type of cell proliferating
examples of metaplasia
epithelial metaplasia (squamous, intestinal, pseudopyloric, etc.) mesenchymal metaplasia (formation of catilage, bone and adipose)
What is barrett esophagus?
when a patient has chronic GERD, the lower parts of the esophagus undergo metaplasia and become a simple columnar epithelium to tolerate the gastric acid rising to the esophagus.
causes of cell injury
hypoxia/ischemia toxins (such as pollutants and CO) infectious agents immunologic reactions, such as inflammatory response genetic abnormalities nutritional imbalance physical agents
how can down syndrome cause cell injuries?
down syndrome causes congenial malformations which lead to cell injury
examples of reversible injury of the membrane
blebbing, distortion of microvilli, loose intercellular exattachments.
reversible injury of the mitochondria
swelling, phospholipid-rich amorphous densities
reversible injury of ER
dilation/swelling, detachment of polysome/ribosome
reversible injury of the nucleus
clumping of chromatin
reversible injury of the cytoplasm
myelin figures
what is fatty change?
loss of lipid-metabolizing enzymes in the liver resulting in accumulation of fat.
examples of fatty change
artherosclerosis and xanthomas
what is atherosclerosis?
cholesterol accumulation in tunica intima
what is xanthoma?
cholesterol/TAG accumulation under the skin
what are russel bodies?
protein accumulation in plasma cells
what are mallory bodies?
cytoskeletal protein accumulation in cells
what is amyloidosis?
accumulation of amyloid
2 types of pathological calcification in the heart
dystrophic (when serum calcium levels are normal) and metastatic (when serum calcium levels are elevated)
changes observed in the nucleus of necrotic cells
pyknosis (nucleus is small), karyorrhexis (the nucleus is bursted), and karyolysis (no nucleus)
changes observed in the cytoplasm of necrotic cells
cytoplasm is eosinophilic, myelin figues, calcium soaps, changes in the mesenchyma.
changes observed in the membrane/extracellular space of necrotic cells
membrane breakage, leakage of intracellular enzymes into the blood (LDH, CK, etc)
What is observed in coagulative necrosis
cells look swollen, firm, and pale. infarcts of solid organs (heart, spleen, kidney) can be seen.
what is observed in caseous necrosis?
cells are white/yellow, cheese-like. can be seen in granulomas
what types of changes are observed in what order when there is cell injury?
biochemical, ultrastructural, light-microscopic, and morphological
characteristics of apoptosis
there is no inflammation. caused by antagonism of BCK2, which leads to the activation of BAX/BAK, release of cytochrome c, and the caspase cascade.
what is autophagy?
cells digest their own organelles and recycle them to provide energy and substrates. If the stress is too severe for the process to cope with it, it results in cell death by apoptosis.
how can ATP levels initiate necrosis?
low levels of ATP cause cell injury and necrosis
how can levels of ROS (reactive oxygen species) initiate necrosis?
high levels of ROS leads to cell injury
3 causes of hypoxia
reduced blood flow due to ischemia and artherosclerosis decreased oxygen affinity of the RBCs due to CO, anemia, and etc. inadequate oxygenation of blood due to low functions of the heart
excessive influx of calcium into the cells result in...
activation of phospholipase, protease, endonuclease, and ATPase
what substance released from a damaged mitochondrium contributes to cell injury and necrosis?
H+
what substance released from a damaged mitochondrium contributes to apoptosis?
cytochrome c
3 immediate results of accumulation of free radicals
lipid peroxidation protein modification or misfolding DNA damage
3 causes of membrane permeability defects
phospholipid loss, accumulation of lipid breakdown products, and cytoskeletal damage
what are the 5 classifications of degeneration?
cellular swelling, fatty change, hyaline change, amyloid change, mucoid change
what are the 5 types of cellular accumulation?
water, fat, amyloid (protein), glycogen, pathologic calcification