week 12- pathology Flashcards
what is aetiology?
causes of pathology, either genetic or acquired
pathogenesis?
sequence of biochemical events that occur after exposure of cells or tissues to injurious agent
morphological changes?
structural alterations in cells or tissues that are either characteristics of a disease or diagnostic of aetiologic process
functional abnormalities?
end result of genetic and structural changes in cells and tissues leads to clinical manifestations
clinical manifestations?
the functional consequences of changes in a cell
how do cells respond to stress?
the cells can adapt this preserves viability and function
what happens if a cells adaptive capability is exceeded with stress?
cell injury develops
if stress is mild, injury is reversible and cell returns to original state
severe or persistant stress results in reversible injury and cell death
physiological adaptions?
are responses of cells to normal stimulation by hormones or endogenous chemical mediators
pathological adaptions?
responses to stress that allow cells to modulate their structure and function to escape injury
hypertrophy?
increase in the size of cells which causes the organ to increase as well
caused by increased functional demand or hormonal stimulation
occurs when cells are incapable of dividing and due to increased production of cellular proteins
hyperplasia?
an increase in the number of cells in an organ
adaptive response in cells capable of replication
physiological= hormonal or compensatory (when a portion of the tissue is removed)
pathological= caused by excessive hormonal or growth factor stimulation
atrophy?
reduction in the size of an organ or tissue due to a decrease in cell size and number
causes: decreased work load, decreased blood supply, loss of endocrine stimulation, decreased protein synthesis, increased protein degradation
eg, broken leg
metaplasia?
reversible change where one adult cell is replaced by another
because cells sensitive to a particular stress are replaced by other cell types better able to withstand the adverse environment
what is reversible cell injury? when does it take place?
in early stages functional changes are reversible if the damaging stimulus is removed
when does cell death occur?
with continuing damage the injury becomes irreversible, the cell cannot recover and it dies
what are some causes of cell death?
schema (inadequate blood supply to organs), infections and toxins
what are the two benefits of cell death?
maintains homeostasis
essential in the development of organs (embryogenesis)
necrosis?
cell death is caused by injury (murder)
enzymes leak out of lysosome into cytoplasm and digest the cell
cell contents leak out though damaged plasma membranes and initiate inflammation
what is the purpose of apoptosis?
serves to eliminate cells that are no longer needed and to maintain a steady number of various cell populations
when does apoptosis occurs?
the cell is deprived of growth factors, DNA or proteins are damaged beyond repair
mediated by the activation of caspases
what are some characteristics of the cell in reversible injury?
cell swelling
loss of microvilli on plasma membrane, loosens intercellular attachments
dilation of ER with detachment of ribosomes
nuclear alterations (clumping of chromatin)
what are some characteristics of the cell in necrosis?
pink dye staining
nuclear shrinkage
breakdown of plasma membrane/ organelle membrane
calcification
leakage and enzymatic digestion of cellular components
what are some characteristics of the cell in apoptosis?
nuclear chromatin condensation
formation of apoptotic bodies (fragments of nuclei and cytoplasm)
what are some causes of cell injury?
Ischemia= low blood supply and results in hypoxia
chemical/ infectious agents?
immune reactions (Type 2 diabetes, immune system causes injury to own cells )
genetic defects (CF)
nutritional imbalances
aging
physical agents
what are the 4 main mechanisms of cell injury?
ATP depletion
mitochondrial damage
calcium influx
ROS
explain ATP depletion.
outcomes?
main cause of necrotic cell death
not enough oxygen so usually happen with hypoxia
results in failure of energy dependant functions
decreased activity of the Na+K+Atpase
influx of ca++ due to failure of ca++ pumps
reduction in protein synthesis
effects of ROS?
dmaage to cell membranes, proteins, inactivation of enzymes
necrosis= increased permeability of cellular membranes
apoptosis= accumulation of damaged DNA and misfolded proteins
autophagy?
the cell eats its own contents because of nutrient deprivation
signalled by proteins that detect their environment
plays a role in cancer, neurodegenerative disorders
what is cellular aging caused by?
the accumulation of cellular damage due
mechanism of cellular aging?
accumulation of DNA damage and defective DNA repair mechanisms
reduced capacity for the cells to divide
defective protein homeostasis
cell senescence?
limited capacity of cell replication because of decreasing telomerase
