Cell injury & death Flashcards
List 3 common causes of reversible cell injury
trauma (concussion, frost bite)
hypoxia
ischemia
What can cause hypoxia?
(Don’t confuse with ischemia)
decreased availability of O2
loss of oxygen carrying capacity of blood (RBC)
Differentiate ischemia from hypoxia.
Ischemia - absence of oxygen and nutrients
Hypoxia - absence of oxygen
List the two ways cells can die.
apoptosis
necrosis
(T/F) All cells can undergo apoptosis.
True
Is inflammation seen during apoptosis?
No
Where is apoptosis commonly seen physiologically?
Physiologic
- embryogenesis constituent feature
- hormone induced changes
- mild trauma or injury removing nonfunctioning cells
Where is apoptosis seen pathologically?
Pathologically
- some tumors
- chemotherapy & radiotherapy
- immune reactions usually by cellular mechanisms
- atrophy terminal event
- graft vs. host disease
- some viral diseases
Apoptosis is induced by what 4 events?
- calcium sensitive endonuclease leading to pyknosis
- transglutaminase activity causes cytoplasmic atrophy
- phagocytes bleb
- gene activation via protein syntehesis of bcl-2, c-myc and p53 promoting apoptosis
What happens to the cell after pyknosis?
karyorrhexis
Death by apoptotic mechanisms.
aging
What are the 4 major forms of necrosis?
coagulative necrosis
liguification necrosis
fat necrosis
caseous necrosis
What does the type of necrosis depend on?
type of tissue and agent
Coagulative necrosis is seen in hypoxic death in all tissues except?
brain
Two common settings for liquefactive necrosis
brain infarct and tissue/brain abscess
What is one of the leading causes of infantile death?
brain trauma
Define fat necrosis.
Saponification of fat cells with calcification due to enzymatic breakdown of lipases. Form of dystrophic calcification. “soap deposits”
What is the most common cause of fat necrosis? second?
trauma
alcoholism
What kind of trauma causes fat necrosis?
Trauma to a fatty organ
Why does resulting trauma in fat necrosis feel hard?
fatty soap; common in breasts
Name types of biopsies?
needle biopsy, core biopsy, incisional biopsy (wedge), excisional biopsy
Describe caseous necrosis.
amorphous debris and surrounding granuloma
What is caseous necrosis a reaction to?
bacteria
What is gangrenous necrosis?
Not a distinct type but a combo pattern; applied to hypoxic limbs, combo of coagulative and liquefactive necrosis
Coagulative necrosis due to
ischemia causes cell death and bacteria capitalizing on
Fibrinoid necrosis
accumulation of eosinophilic amorphous proteinaceous material in tissue matrix
staining pattern reminiscent of fibrin
What are the risks of angioplasty?
procedural, hemorrhagic, and reperfusion injury; arthrosclerosis can be dislodged
Would you use angioplasty for a middle cerebral artery?
Not if there is liquifactin necrosis in the brain; can cause hemorrhage
What type of necrosis might be found in the feet of a diabetic?
Gangrenous necrosis
What represents irreversible cellular damage?
nuclear pyknosis
What is the most commonly occluded artery in the brain?
middle cerebral artery
What is a likely pathologic event from an occluded MCA?
cerebral softening from liquefactive necrosis
Blood culture with Strep. viridans. 1 cm vegetation on mitral valve. Pathologic changes?
Necrosis
