BIOMED NOTES 24/25

Structural classification Types of material that binds the skeleton Fibrous joint United by fibrous tissue Amount of movement depend on fiber length Sutures  Bones separated, held tautly by thin layer of fibrous tissue  Extreme tight union Little/no movement  Synostoses  Disappear at old age  Skull Fontanelles Syndesmosis 2 bones united by a sheet of fibrous tissue May be a ligament/interosseous membrane  Slight movement Between radius ulna Between tibia fibula  Gomphosis  Peg and socket Fixation of teeth in alveolar sockets: mandible, maxillae Periodontal ligament connects dental cement with alveolar bone Cartilaginous joint United by cartilage  Primary  Synchondroses  Articulating bones united by hyaline cartilage  Immovable: synarthrosis  Epiphyseal plate  Between costal cartilage of first rib and sternum  Secondary Symphyses Articular surfaces covered by hyaline cartilage United by fibrocartilage  Slight...

  PROGRAMMED CELL DEATH (PCD) Apoptosis type I cell death Apoptosis = programmed cell death • Main features: ➢ Chromatin condensation and DNA fragmentation ➢ Formation of blebs on the cell surface ➢ Breakdown of cytoskeleton and nuclear envelope ➢ Cell shrinkage and formation of apoptotic bodies      Apoptosis (TEM): https://www.sciencedirect.com/science/article/pii/S0955067404001474 Apoptosis is mediated by intracellular proteolytic cascade Caspases = family of protease enzymes - catalytic activity Intracellular proteolytic cascade = irreversible amplifying chain reaction involve initiator and executioner caspases that is destructive Procaspase = inactive caspase precursor  Initiator procaspase = inactive caspase precursor activate downstream executioner caspase  Executioner caspase = degrade proteins  Intrinsic pathway (Mitochondrial pathway) Extrinsic pathway Triggered by cellular stressors  Oxidative stress free radicals and not enou...