BIOL 212 Lecture Notes - Lecture 5: Bone, Epithelium, Osteoblast
Document Summary
Biology 212 - lecture 5 - the muscular system. Bone forms concentric rings of matrix which is known as osteon. Bone cells are trapped within cavities (bones) Organized nested rings in periphery of bones. Depending on body signals, bone will change from spongy bone to compact bone and back again. Canaliculi transfer nutrients from one cells to another. Mineralized matrix- no diffusion through the matrix. Protoplasmic (arm) extension of adjacent cells connect within canaliculi. Waste, nutrients, gases, etc. diffuse from cell to cell. Latin for little mouse (myo, mys, sarco) Elongated cells packed with contractile proteins (myosin and actin) Excitability - responds to external stimuli (hormones and nervous stimulus) Contractility - actively shortens along longitudinal axis. Extensibility - can stretch beyond original length, without tearing. The complete action of the organ is the result of the action of the individual cells. Muscle organs = muscles fibers (cells) + connective tissue + nervous tissue + epithelial tissue.
