cell injury Flashcards
List the causes of cell injury
trauma oxygen deprivation - MI - atheroma chemical agent including iatrogenic injury infectious agent immunological reaction - autoimmune - arthritis genetic defect nutritional imbalance physical agent aging
what does the cellular response to injury depend on
what caused it
duration
severity
what do the consequences of cell injury depend on
type of cell - bone more susceptible
status - dividing more susceptible
which systems are more vulnerable
cell membrane integrity
ATP generation
protein synthesis and growth
integrity genetic apparatus
mechanisms of cell injury - general
structural and chemical components related - multiple secondary effects
cellular function lost before death lost before morphology lost.
what is hyperplasia
too many cells
what is atrophy
cell shrinkage
what is hypertrophy
cell enlargement
what is metaplasia
reversible change of 1 cell type to another
what is dysplasia
cytological and genetic signs of malignancy but no invasion of local tissue
describe apoptosis
no inflammation programmed pathological/physiological death of 1 cell - no damage to other tissue fragmentation of DNA active
what is necrosis
inflammation
damage to surrounding tissue
no ATP needed - caused when run out of ATP
always pathological
causes of apoptosis
embryogenesis
deletion auto-reactive T cell
hormone dependant physiological involution - breast
cell deletion in proliferating populations - gut/cancer
irreparable DNA damage
Example of metaplasia
smoking lung epithelium squamous - columnar
pregnancy cervix epithelium - columnar - squamous because of acids.
oesophagus acid reflux stratified squamous - columnar
example of hyperplasia
physiological - hormonal/compensatory - gland grow thicker and cells multiply - uterus
pathological - hormonal/growth factor stimulation - TSH drive proliferation of thyroid follicular glands
pathological - carcinoma (increased mitotic cells)
