Atrophy

Atrophy

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  ATROPHY PRESENTED BY: MARYAM MANZOOR LECTURERPHARMACOLOGY RASHID LATIF COLLEGE OF PHARMACY
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  DEFINITION • Atrophy isshrinkage in the size of cells by the loss of cell substance.
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  • When asufficient number of cells are involved, the entire tissue or organ is reduced in size, or atrophic . • Although atrophic cells may have diminished function, they are not dead.
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  TYPES ATROPHY PHYSIOLOGIC PATHOLOGIC
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  PHYSIOLOGIC ATROPHY • Uterusfollowing childbirth • Post menopausal endometrium----- vaginal atrophy • Shrinkage of mammary glands after lactation.
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  CAUSES OF PATHOLOGICATROPHY 1. Decreased workload 2. Decreased blood supply 3. Inadequate nutrition 4. Inadequate innervation (neuropathic) 5. Loss of endocrine stimulation 6. Pressure
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  • Both typesof causes lead to the smaller cell size at which survival is still possible; a new equilibrium is achieved between cell size and diminished blood supply and nutrition.
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  Atrophic Brain NormalBrain
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  UNDERLYING MECHANISM • Cellularatrophy results from a combination of decreased protein synthesis and increased protein degradation. 1. Protein synthesis decreases because of reduced metabolic activity.
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  2-PROTEOSOME PATHWAY • Thedegradation of cellular proteins occurs mainly by the ubiquitin-proteasome pathway. • Nutrient deficiency may activate ubiquitin ligases, which attach multiple copies of the small peptide ubiquitin to cellular proteins and target them for degradation in proteasomes----- increased proteolysis.
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  3- AUTOPHAGY • Atrophyalso is associated with autophagy, with resulting increases in the number of autophagic vacuoles. • Autophagy is the process in which the starved cell eats its own organelles in an attempt to survive. • Atrophy can be reversible