Cellular pathology

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Cellular pathology

  1. 1. Cellular Pathology<br />“All organ injuries start with structural or molecular alterations in cells” concept began by Virchow in 1800's.<br />
  2. 2. NORMAL CELL<br />
  3. 3. NORMAL CELL<br />present day study of disease attempts to understand how cells react to injury.<br />at the subcellular or molecular level.<br />
  4. 4. NORMAL CELL<br />all cells share the basic organelles for the synthesis of proteins, lipids, carbohydrates; energy production.<br />transport of ions and other substances.<br />to understand pathology, review normal structure and function of cells.<br />“you cannot appreciate the abnormal before you understand <br /> the normal”<br />
  5. 5. Plasma membrane<br />phospholipid bilayer with embedded proteins / glycoproteins / glycolipids.<br />semipermeable membrane with pumps for ionic / osmotic homeostasis<br />
  6. 6. Nucleus<br /> nuclear envelope / nuclear pores<br />chromatin (euchromatinvsheterochromatin)<br />nucleolus (synthesis of ribosomal RNA)<br />
  7. 7. Mitochondria<br />inner & outer membranes, cristae<br />intermembranousand inner matrix compartments<br />oxidative phosphorylation (main source of ATP)<br />
  8. 8. Endoplasmic reticulum (ER),Ribosomes & Golgi Apparatus<br />rough (RER) vs smooth (SER) endoplasmic reticulum<br />ribosomes(free in cytosol or attached to RER)<br />polysomes(threaded by mRNA).<br />condensing vacuoles / secretoryvesicles<br />
  9. 9. Lysosome<br />enzymatic (acid hydrolases) digestion of materials in the cell<br />endocytosis<br />phagocytosis/ phagosome; pinocytosis / pinocytotic vesicle; receptor-mediated endocytosis<br />
  10. 10. Peroxisome<br />enzymes (egcatalase, oxidases) ! metabolism of hydrogen peroxide & fatty acid<br />
  11. 11. CELL ADAPTATION, CELL INJURY and CELL DEATH<br />DEFINITIONS AND TERMINOLOGY<br />Homeostasis : cells are able to maintain normal structure and function (eg ion balance, pH, energy metabolism) in response to normal physiologic demands.<br />
  12. 12. Cellular Adaptation<br />as cells encounter stresses, either excessive physiologic demand or some pathologic stimuli, they may make functional or structural adaptations to maintain viability / homeostasis.<br />
  13. 13. Cellular Adaptation<br />cells may respond to these stimuli by either increasing or decreasing their content of specific organelles.<br />adaptive processes: atrophy, hypertrophy, hyperplasia and metaplasia are forms of adaptation.<br />
  14. 14.
  15. 15. Cell Injury<br />if the limits of adaptive response are exceeded, or in certain instances when adaptation is not possible, a sequence of events called cell injury occurs.<br />
  16. 16. Cell Injury<br />a) Reversible Cell Injury<br />removal of stress will result in complete structural and functional integrity to be restored.<br />
  17. 17. Cell Injury -> Cell Death<br />Irreversible Cell Injury / Cell Death<br />if stimulus persists (or severe enough from the start) the cell will suffer irreversible cell injury and death.<br />cell death is one of the most crucial events in pathology and can affect any type of cell.<br />
  18. 18.
  19. 19. Cell Death<br />Necrosis: type of cell death characterized by severe membrane injury and enzymatic degradation; always a pathologic process.<br />Apoptosis: regulated form of cell death; can be physiologic or pathologic process.<br />

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