cellular adaptations I and II Flashcards
What are the 3 proliferative capacities of tissues
continuously dividing cells (or labile cells)
stable tissues
permanent tissues
ex of continuously dividing cells/labile cells
hematopoietic cells surface epithelia (upper airway, GI, skin...)
definition of stable tissues
minimal replication usually
proliferate in response to injury
parenchyma of most solid organs like kidney, liver, pancreas
endothelial cells, fibroblasts, smooth muscle
definition of permanent tissues
non-proliferative
ex of permanent tissues
neurons
cardiac muscle cells
define hypertrophy
increase in size of cells, leading to increased organ size
what kinds of cells undergo hypertrophy?
cells that have limited or no capacity to divide
physiologic hypertrophy can occur due to
increased functional demand or hormonal stimuli
ex of physiologic hypertrophy
skeletal muscle hypertrophy in weight lifter
uterus in pregnancy
ex of pathologic hypertrophy
cardiac muscle hypertrophy in HTN
define hyperplasia
increased cell number
in what kind of cells does hyperplasia occur?
those that are able to divide (labile and stable)
ex of physiologic hyperplasia
female breast at puberty, pregnancy
compensatory hyperplasia in liver after partial resection
would healing-connective tissue
pathologic hyperplasia examples
excessive hormones–>endometrial hyperplasia
benign prostatic hyperplasia
skin warts and mucosal lesions associated with viruses (papilloma virus)
what differentiates pathologic hyperplasia from cancer?
pathologic hyperplasia cells respond to normal regulatory mechanisms (it’s just that there is excessive stimulation)
in cancer, abnormal regulation
however, pathologic hyperplasia increases the risk for cancer
enlargement of uterus in pregnancy is ex of
both hyperplasia and hypertrophy
atrophy definition
decrease in size of cell due to loss of cell matter
causes of atrophy include
physiologic and pathologic
ex of physiologic atrophy
endometrium at menopause (loss of hormones)
ex of pathologic atrophy
decreased function (broken arm in cast)
loss of innervation (trauma to nerve)
inadequate nutrition
metaplasia defintion
one adult cell type is replaced by another adult cell type (to better tolerate the stress)
- is an adaptive process to chronic stress (ex. chronic smoking, chronic gastric acid reflux..)
- stem cells differentiate through a new pathway
- may be associated with greater chance of cancer