Cell Injury Flashcards
reversible functional and structural responses to changes in physiological and some pathological stimuli to maintain homeostasis
adaptation
ex: hyperplasia/hypertrophy, atrophy/ metaplasia
hypertrophy vs hyperplasia
hypertrophy: cells increase in size (occurs in tissue whose cells have limited capacity to divide - muscle)
hyperplasia: cells increase in number
T/F: hyperplasia is controlled and the body has a mechanism to stop further profileration
TRUE: hyperplasia is controlled - remove stimulus (hormones, other signaling molecules) and proliferation ceases
*may progress to neoplasia if it becomes uncontrolled
atrophy causes decrease in:
a. cell number
b. cell size
BOTH, due to apoptosis (decrease cell number) and decreased protein synthesis and increased degradation (decrease cell size)
metaplasia
reversible change whereby one adult cell type is replaced by another
cell type vulnerable to particular stress is replaced by a less vulnerable cell type
change results from altering the maturation of stem cells
reversible change whereby one adult cell type vulnerable to a type of stress is replaced by another which is less vulnerable
metaplasia - change resulting from alteration of maturation of stem cells
drawback of metaplasia
reversible change - one adult cell type is replaced by another that is better equipped to handle a stress
for example, if someone has Barrett’s esophagus (gastric acid reflux), cells of the esophagus that are contacted by acid will become mucus-secreting columnar (rather than squamous) for better protection
drawback: loss of specialized function, growth deregulation
in smoker’s bronchi, ciliated columnar cells transform into tougher squamous cells
what is this process called and what is the risk of this physiological adaptation?
metaplasia - replacing cells with others better equipped for a stress
drawback: loss of specialized function and growth deregulation
as stress continues, malignant transformation can occur
which of these represent irreversible cell injury:
a. decreased ATP
b. cell swelling
c. severe mitochondrial damage
d. increased [Ca2+]
e. DNA damage
explain your choice(s)
irreversible:
c. severe mitochondrial damage —> leakage of apoptotic proteins, reduced ATP
d. increased [Ca2+] —> catabolic enzymes, increased mitochondrial permeability
is cell swelling reversible or irreversible cell injury?
it CAN be reversible, but can also lead to formation of membrane blebs —> necrosis
what does increased eosinophilia seen in a cell indicate
irreversible cell injury (necrosis)
lysosome rupture, mitochondrial damage, myelin figures
*eosin is anionic, acts as acidic dye (binds positively charged proteins)
how will cells with hypoxic injury appear?
more eosinophilic (pink) - acidic dye, binds positively charged molecules
hypoxia —> decreased ATP —> increase in anaerobic glycolysis and lowered pH (acidic)
____ is a passive, irreversible, unregulated response to injury - no energy required
necrosis -
lysosomal enzymes enter cytoplasm, leakage of cell contents through damaged plasma membrane into ECS causes inflammation, denaturation of cellular proteins
always pathological
appears eosinophilic
coagulative necrosis
underlying tissue architecture is preserved
example: cardiac infarction
liquefactive necrosis
underlying tissue architecture is lost, viscous/liquid
example: cerebral infarction
coagulative vs liquefactive necrosis
coagulative: underlying tissue architecture is preserved (ex - cardiac infarction)
liquefactive: underlying tissue architecture is lost, viscous/liquid (ex - cerebral infarction)
what type of necrosis follows cardiac infarction, and cerebral infarction, respectively? explain
cardiac infarction - coagulative necrosis (tissue architecture preserved) - muscle tissue is strong
cerebral infarction - liquefactive necrosis (tissue architecture lost) - brain tissue is soft, does not have strong ECM
gangrenous necrosis
clinically, and ischemic limb with coagulative necrosis (underlying tissue architecture preserved)
“wet” if bacterial superinfection —> then becomes liquefactive necrosis
fat necrosis typically result from release of…
activated pancreatic lipases
(such as in acute pancreatitis)
caseous necrosis
tissue architecture and cell outlines obliterated
surrounded by granuloma inflammation (walled off)
mainly seen in tuberculosis
match to apoptosis or necrosis:
a. consumes energy
b. passive response (no energy)
c. cell shrinking
d. cell swelling
apoptosis: consumes energy, cell shrinking (blebs —> apoptotic body)
necrosis: passive (no energy), cell swelling (—> disruption of PM)
