Hyperplasia
Increase of size of organs due to numerical excess of the cells
Response to prolonged stimulus
Organs /tissues that are capable of division
Prerequisite: good blood supply
Causative factors:
- hormonal effects (adrenal cortex, prostate, male breast, acromegaly…)
- prolonged antigenic stimulus (follicular hyperplasia)
- drugs (cyclosporin A – gingival hyperplasia)
- metabolic causes (obesity)
- compensatory
- unknown
Benign prostatic hyperplasia
Hormonal background
Starts around 50 ys, peak incidence: 70-80 years
Accumulation of the perirurethral glands and stroma
Testosterone-production is imperative (not in eunuchs!)
Accumulation of locally produced dihidrotestosterone (DHT)
Major complication: urethral and bladder neck compression, the urine outflow is blocked)
Beningn prostatic hyperplasia
Hypertrophic urinary bladder
Dilatation of the bladder
Hydroureter
Hydronephrosis
Renal insufficiency
Ascensing infections
(pyelonephritis)
Hypertrophy
Increase in size of the organ, but the number of cells is unchanged
Tissue that are non capable of division (muscle)
Characteristically: against increased forces
Increased diameter of te cells, increased DNA content
Striated muscle (physical activity, sports)
Heart muscle
left chamber: hypertension, aortic stenosis
right chamber: increased pulmonary resistance (cor pulmonale chr.)
Congenital pylorus-stenosis
Hypertrophy of the urinary bladder
Hirschsprung-disease
Metaplasia
A mature tissue is replaced by an other mature tissue
Indirect metaplasia (abnormal differentiation of reserve cells)
Epithelial metaplasia:
glandular epithelium squamous epithelium (squamous metaplasia) – bronchus, salivary glands /sialometaplasia/, cervix, pancreas
glandular epithelium another type of glandular epithelium (intestinal metaplasia)
(stomach; esophagus: Barrett-metaplasia; breast: apocrine metaplasia)
Mesenchymal metaplasia:
abnormal differentiation of pluripotent cells (cartilage, bone, etc.)