Description
Atrophy - E. Cells decrease in size
P. Still functional; imbalance between protein synthesis and degradation. Essentially
there is an increase in the catabolism of intracellular organelles, reducing structural
components of cell
Physiologic: thymus gland in early childhood
Pathological: disuse (muscle atrophy d/ decrease workload, pressure, use, blood supply,
nutrition, hormonal stimulation, or nervous stimulation)
Hyperplasia - E: cells increase in number, mitosis (cell division) must occur, size of cell
does not change
Phys: increased rate of division, increase in tissue mass after damage or partial
resection; may be compensatory, hormonal, or pathologic
Patho: abnormal proliferation of normal cells usually caused by increased hormonal
stimulation (endometrial). increase of production of local growth factors
Ex: removal of part of the liver lead to hyperplasia of hepatocytes. uterine or mammary
gland enlargement during pregnancy
Dysplasia - E. Not true adaptation; Cells abnormal change in size, shape, organization
(classified as mild, moderate, severe)
P. caused by cell injury/irritation, characterized by disordered cell growth. aka atypical
hyperplasia or pre-cancer, a disorderly proliferation
Physiologic: N/A
Pathologic: squamous dysplasia of cervix from HPV shows up on pap smear, breast
cancer development; pap smears often show dysplastic cells of the cervix that must
undergo laser/surgical tx
Metaplasia - E: reversible change, one type of cell changes to another type for survival
P: reversible; results from exposure of the cells to chronic stressors, injury, or irritation;
Cancer can arise from this area, stimulus induces a reprogramming of stem cells under
the influence of cytokines and growth factors
Ex: Patho: Columnar cells change to squamous cells in lungs of smoker or normal
ciliated epithelial cells of the bronchial linings are replaced by stratified squamous
epithelial cells.; Phys: Barrett Esophagus- normal squamous cells change to columnar
epithelial cells in response to reflux, aka intestinal metaplasia
Hypoxia injury - E. inadequate oxygenation of tissues
P. decrease in mitochondrial function, decreased production of ATP increases anaerobic
metabolism. eventual cell death.
C.M. hypoxia, cyanosis, cognitive impairment, lethargy