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Pathology & Physiology (Fach) / PIPs (Lektion)
Hypertrophy, hyperplasia, Atrophy, Metaplasia
Diese Lektion wurde von Lydiamarieluise erstellt.
- Def. Hypertrophy + example "The enlargement of a tissue or organ due to an increase of the cell size" 1. Abnormal: hypertrophy of the heart muscle due to increased blood pressure
- Def. Hyperplasia + Example "The enlargement of a tissue or organ due to an increase in the number of cells" --> only in dividing cells (not in cardiac/skeletal muscle) 1. Normal: during pregnancy the uterus grows bigger due an enlargement of the smooth muscle mass in the muscular wall (hormonal stimulus) --> Hyperplasia + Hypertrophy 2. Abnormal: Prostatic hyperplasia --> Hyperplasia + Hypertrophy
- Def. Atrophy + Example "The reduction in mass of a tissue or organ due to a reduction in cell size, cell number (apoptosis) or both" --> Pathogenesis: lack/loss of blood supply and innervation 1. Normal: shrinking of the uterus during the menopause due to the lack of oestrogen and progesterone because the ovaries stop their production/atrophy of the thymus at puberty 2. Abnormal: shrinking of limbs in a cast after an accident due to the loss of muscle mass (immobilisation)
- Def. Metaplasia + Example "Change of one mature adult tissue into another" --> cellular adaption to invironmental influences 1. Abnormal: a)Changes in the airway of people who smoke (squamous metaplasia): ciliated columnar epithelium changes into stratified squamous epithelium which is more resilient and protective but not specialised (no cilia) b) Barrett's eosophagus: the epithelium of the gastroeosophageal transition zone transforms from normal squamous epithelium to intestinal type of epithelium (glandular epithelium) due to acid reflux --> can cause adenoid cancer
- Def. Ectopia (Heterotopia) "The presence of normal tissue in the wrong place as a developmental abnormality" --> Congenital, due to embryonic cells getting lost
- Difference Neoplasia and the designated processes - neoplastic processes are irreversible, while cellular adaptations (hypertrophy, hyperplasia, metaplasia, atrophy) are potentially reversible
- Molecular mechanisms behind cellular changes 1. Growth factors - paracrine regulations - hormonal mechanisms - synaptic mechanisms 2. Up- or downregulation of cell receptors 3. New protein synthesis
- Sorts of cell growth (4) 1. Multiplicative (number) 2. Auxetic (size) 3. Accretionary (ECM) 4. Combined
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