Cellular stress/toxic injuries: Adaptation, injury, and death Flashcards
What are the 4 adaptation responses?
Hypertrophy (increase size)
Hyperplasia (increase #)
Atrophy (shrinkage of cell/decreased metabolic activity)
Metaplasia (change in phenotype)
What is the response to a patient with chronic hypertension or faulty valves?
The heart will go through hypertrophy (left ventricle), if too severe it will cause damage to the heart.
What are the GF required for hypertrophy of the heart?
ANF GATA 4 (transcription factor) IGF-1 MEF2 (myocardial enhancing factor) NFAT (nuclear factor activating T-Cells)
What are some vasoactive elements that will cause hypertrophy of cardiac muscle?
alpha adrenergic agonist
Endothelin-1
AT-2 (angiotensin 2)
What causes hypertrophy and hyperplasia of the uterus?
Large concentrations of estrogen.
What is the response to liver damage?
Hyperplasia
What undergoes rapid cell division when erythropoietin is present?
The bone marrow, to be more specific progenitor cells.
What is the characteristic response to viral infections? Give an example and why.
Hyperplasia is a characteristic response
HPV is an example of this, it causes skin warts and several mucosal lesions composed of hyper plastic epithelium.
Two organs that undergo atrophy during development are…
Notochord
Thyroglossal duct
Prolonged disuse of cells such as skeletal muscle fibers will cause..
Atrophy: Decrease in the size of the cells and it might cause apoptosis of certain cells.
What are some common causes of atrophy
Loss of innervation to tissue Ischemia Inadequate nutrition (cachexia) Loss of endocrine stimulation (loss of GF) Pressure on tissue
The brain and heart goes through what process as we get older?
Atrophy due to atherosclerosis (senile atrophy), this also happens to the heart.
Mechanism for atrophy
Degradation of proteins (ubiquitin-proteasome pathway)
Autophagy of organelles to match blood supply
Discoloration because of lipofuscin granules (brown)
What happens to the respiratory epithelium for cigaret smokers?
Metaplasia of respiratory epithelium
ciliated columnar epithelium to stratified squamous epithelium.
What are some common causes of metaplasia?
Vitamin A deficiency: squamous metaplasia in respiratory system
Stone formation in excretory ducts: pancreas, salivary gland, or bile duct. Columnar to squamous
Smoking: Ciliated columnar to stratified squamous
What causes Barrett Esophagus?
The patient has GERD and the esophageal squamous epithelium changes to intestinal like columnar epithelium.
This can develop into adenocarcinoma (glandular carcinoma)
What is myositis ossificans? (it is from a result of injury)
Occurs in intramuscular hemorrhage, which results in the formation of cartilage, bone, or adipose tissue.
What are key features of necrosis (6)
Irreversible injury
Cell size: swelling
Nucleus: pyknosis->karyorrhexis->karyolysis
Plasma membrane: disrupted
Cellular contents: leak out of cell
Localized inflammation
What are key features of apoptosis (6)
Programed death
Cell size: reduced
Nucleus: Fragmentation
Plasma membranes intact, but altered structure.
Cellular contents: apoptotic bodies, buds of cells
What is pyknosis, karyorrehexis, and karyolysis?
Pyknosis: condensation of the nucleus (increased basophillia color)
Karyorrehexis: fragmentation of nucleus and disappears
Karyolysis: break down of DNA, fading basophillia color.
Coagulative necrosis: features and location
Location is all organs except the brain
Caused by ischemia to target tissues, localized areas are considered infants.
Liqiefactive Necrosis: features and location
Generally happens in the CNS (brain)
Caused by digestion of dead cells by leukocytes, which results in a liquid mass. There is a creamy yellow pus like material.
Gangrenous necrosis: features and location for both dry and wet
Location in the lower extremities of the body when they lose blood supply.
Normal necrosis (dry), but if there is an infection superimposed on them it will cause wet gangrene, which is an increased level of liquefactive necrosis.
Caseous necrosis: features and location
This is found in infections such as TB infections, where there is a characteristic granuloma formation.
There will be a white appearance of necrosis, with fragmented/lysed cells enclosed by an inflammatory boarder.
Fat necrosis: features and location
From the release of pancreatic lipase, which are from acinar cells during acute pancreatitis.
This process includes the break down of fat tissue and replace it with calcium deposits. There will be presence of saponification (white chalky substances).
Fibinoid necrosis: features and location
Happens in immune responses involving blood vessels like Vasculitis syndromes.
Antigen-antibody complexes collect on the walls of arteries, which causes fibrin to leak out.
When stained with H and E stains it will be a bright pink and amorphous appearance.
Dystrophic calcification
Cellular debris from necrotic tissue will provide a location for calcium and other minerals to calcify. It can also happen in aging or damaged heart valves.
This only happens if necrotic tissue is not removed properly. Happens in coagulative, caseous, or liquefactive.
This also happens with asbestos in the lungs, create dumbbells.
What happens if a cell runs out of ATP?
This will cause necrotic death because the cell will experience
Cell swelling because no Na/K pump action
Lactic acid build up=decreased pH
Calcium build up= failure of Ca pumps
ER stress response
Damage to mitochondrial and lysosomal membranes.