BIOSC-139 Lecture Notes - Lecture 27: Endoplasmic Reticulum, Cardiac Muscle, Skeletal Muscle
22 Oct 2020
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Similar to other cells, multinucleated, lots mitochondria. Has lots of glycosomes, myoglobin (o2 storage) Myoglobin holds extra oxygen only in skeletal muscle (not as much in cardiac) Back-up supply of oxygen in muscle cell provide more energy. Myofibrils pack the cell (80% cell volume) 10x diameter of other cells, length - some 30cm long! Opening that lets extracellular flui go out. Talk to the cell membrane that makes up sr store calcium tiny invaginations of the sarcolemma filled with interstitial fluid. They help propagate the action potentials (electrical signals) down the fiber. Sacroplasmic reticulum the specialized endoplasmic reticulum of cardiac muscle and skeletal striated muscle that functions especially as a storage and release area for calcium!! Terminal cisterns - part of the sr and align with the t tubules to form a triad. Terminal cisterns release ca++ to trigger muscle contractions. Triad sandwich of sr and t-tubule.
