cellinjuryandhypertrophy pathology .pptx

cellular injury and hypertrophy

1. CELL INJURY AND HYPERTROPHY Presented By TALHA SHAHID STUDENT OF PHARM D D EPARTMENT OF PHARMACY SBBU

2. CELL INJURY/ ADAPTION AND CELL DEATH Cells are structural and functional unit of body which constantly keep on adjusting their structure and function to accommodate changing demands and extracellular stresses in order to maintain homeostasis.

3. CELL INJURY/ ADAPTION AND CELL DEATH As cells encounter physiologic stresses or pathologic stimuli, they can undergo adaptation, achieving a new state and preserving its function. If the adaptive capability is exceeded or if the external stress is inherently harmful, cell injury develops.

4. CELL INJURY/ ADAPTION AND CELL DEATH Within certain limits injury is reversible, and cells return to a stable baseline; however, severe or persistent stress results in irreversible injury and death of the affected cells.

5. MECHANISMS OF CELL INJURY

6. CELLULAR ADAPTATION Adaptations are reversible changes in the number, size, metabolic activity, or functions of cells in response to changes in their environment. Physiologic adaptations usually represent responses of cells to normal stimulation by hormones or endogenous chemical mediators (e.g., the hormone-induced enlargement of the breast and uterus during pregnancy). Pathologic adaptations are responses to stress that allow cells to modulate their structure and function and thus escape injury. Pathologic adaptations can be either hypertrophy, hyperplasia, atrophy, metaplasia.

7. 1- HYPERTROPHY Hypertrophy is an increase in the size of cells resulting in increase in the size of the organ.

8. In hypertrophy there are no new cells, just bigger cells containing increased amounts of structural proteins and organelles. Hypertrophy occurs when cells have a limited capacity to divide. Hypertrophy can be physiologic or pathologic.

9. PHYSIOLOGICAL HYPERTROPHY Occurs in response to normal physiological requirement. EXAMPLES Uterus enlargement in pregnancy due to increased estrogen stimulated smooth muscles hypertrophy. Increased skeletal muscles due increased workload.

10. PATHOLOGIC HYPERTROPHY Occurs in response to any pathological condition. EXAMPLES Cardiac enlargement that occurs with hypertension. Smooth muscles hypertrophy in pyloric stenosis

11. MECHANISMS INVOLVING CARDIAL HYPERTROPHY Mechanical Triggers (stretch) Trophic Triggers (activation of Alpha adrenergic receptors) Stimulation of signal transduction----- synthesis of genes that form proteins like myofilaments----- increased force and contraction---------- increased work demand--- cell size increased.

12. An adaptation to stress such as hypertrophy can progress to functionally significant cell injury if the stress is not relieved.