Cellular Physiology

• Organelles
  • Mitochondria
    • Outer mitochondrial membrane
    • Intermembrane space where $\mathrm{H}{}^{+}$ ions are pumped into which is used to synthesise ATP
    • Inner mitochondrial membrane where the electron transport chain occurs
    • Inner mitochondrial matrix where other metabolic processes take place (e.g. citric acid cycle, fatty acid metabolism and the urea cycle)
  • Endoplasmic reticulum
    • Rough ER more prominent in protein producing cells (e.g. antibody-producing plasma cells)
    • Smooth ER is for steroid and lipid synthesis; therefore more prominent in cells of the adrenal cortex for example
      • In smooth muscles it is known as the sarcoplasmic reticulum and serves as a intracellular store of $\mathrm{Ca}{}^{2+}$ hat releases $\mathrm{Ca}{}^{2+}$ following depolarisation
  • Golgi apparatus
    • For modification and packaging of proteins in preparation for secretion
    • When the Golgi apparatus receives a protein from the ER, it is modified through the addition of carbohydrate or phosphate groups, processes known as glycosylation and phosphorylation
  • Lysosomes
    • Found in all cells, but are particularly common in phagocytic cell
    • Contain digestive enzymes, acid and free radical species and they play a role in cell housekeeping (degrading old, malfunctioning or obsolete proteins), programmed cell death (apoptosis) and the destruction of phagocytosed microorganisms

Sources

• Chambers, D., Huang, C., Matthews, G., 2019. Basic Physiology for Anaesthetists, 2nd ed. Cambridge University Press. https://doi.org/10.1017/9781108565011