Injury and Cell Death Flashcards
What are the two types of cellular adaptation?
Hyperplasia
Hypertrophy
What is hyperplasia?
Increased cell proliferation
What is hypertrophy?
Cell enlargement
What cells will undergo hyperplasia?
Cells that are able to undergo mitosis
What cells will undergo hypertrophy?
Cells that can’t carry out mitosis (ex cardiac cells)
What is physiological hyperplasia?
Normal and controlled increase of cells in a tissue or organ in response to stimulus
Reversible
Explain hormonal hyperplasia
Hormones stimulate organ or tissue to increase its functional capacity
- Ex. Uterus in pregnancy
Explain compensatory hyperplasia
Takes place to replace lost or damaged tissue
ex. Liver will regenerate with part of it is removed
This type of hyperplasia takes place when there is excess hormonal stimulation
Pathological hyperplasia
Is pathological hyperplasia controlled or uncontrolled?
Abnormal but controlled
Can atrophy be physiological?
Yes! Common during normal development
Thymus atrophy in childhood
Uterine involution after childbirth
What is metaplasia?
Reversible change where one adult cell type is replace by another adult cell type
Most common epithelia: columnar to squamous in smokers
This is a manifestation of adaptation or sub-lethal cell injury
Intracellular accumulations (metabolites)
normal/abnormal
endogenous/exogenous
Ex calcification can cause injury or happen after injury
This is what happens when a cell isn’t able to adapt or is exposed to damaging agents
Cell injury
What are the hallmarks of reversible cell injury?
Decreased oxphos
ATP depletion
Cell swelling r/t ion conc. and water influx
These are two major microscopic changes seen with reversible cell injury
Cell swelling
Fatty changes
This is the process that ultimately underlies all causes of cell death
Hypoxia
What are the two types of cell death?
Necrosis
Apoptosis
Is cell death always pathological?
No! Apoptosis can be part of normal development
Necrosis is ALWAYS pathological
What are the characteristics of necrotic cell death?
Plasma membrane rupture
Internal organelle and nuclear membrane rupture
Acute inflammatory response
What are the characteristics of cell death via apoptosis?
Cell DNA and/or proteins damaged beyond repair
Programmed cell death
Cell fragments, nuclear dissolution
No acute inflammatory response
Describe the characteristics of coagulative necrosis
Often caused by ischemia
Ischemia —> lack of oxphos
ATP pumps failing —> cells swell
Anaerobic glycolysis —> acidic env and denaturation of structural and enzymatic enzymes
Eosinophilic cells may persist for days to weeks
What is a localized area of coagulative necrosis called?
Infarct
Describe the characteristics of liquefactive necrosis
Digestion of dead cells —> tissue replaced with liquid, viscous mass (infection —> pus)
Ischemic dmg to brain
