Atrophy

Atrophy

1. ATROPHY Presented by: Maryam manzoor Lecturer pharmacology Rashid latif college of pharmacy

2. DEFINITION Atrophy is shrinkage in the size of cells by the loss of cell substance.

3. When a sufficient 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.

4. TYPES

5. PHYSIOLOGIC ATROPHY Uterus following childbirth Post menopausal endometrium ----- vaginal atrophy Shrinkage of mammary glands after lactation.

6. CAUSES OF PATHOLOGIC ATROPHY Decreased workload Decreased blood supply Inadequate nutrition Inadequate innervation (neuropathic) Loss of endocrine stimulation Pressure

7. Both types of 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 .

8. Atrophic Brain Normal Brain

9. UNDERLYING MECHANISM Cellular atrophy results from a combination of decreased protein synthesis and increased protein degradation . Protein synthesis decreases because of reduced metabolic activity.

10. 2-PROTEOSOME PATHWAY The degradation 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.

11. 3- AUTOPHAGY A trophy also 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