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Sarcoplasm is the cytoplasm of a muscle cell. It is comparable to the cytoplasm of other cells, but it contains unusually large amounts of glycogen (a polymer of glucose), myoglobin, a red-colored protein necessary for binding oxygen molecules that diffuse into muscle fibers, and mitochondria.
The unusual microscopic anatomy of a muscle cell gave rise to its terminology. The cytoplasm in a muscle cell is termed the sarcoplasm; the smooth endoplasmic reticulum of a muscle cell is termed the sarcoplasmic reticulum; and the cell membrane in a muscle cell is termed the sarcolemma. [9] The sarcolemma receives and conducts stimuli.
Mitochondrial biogenesis is the process by which cells increase mitochondrial numbers. [1] [2] It was first described by John Holloszy in the 1960s, when it was discovered that physical endurance training induced higher mitochondrial content levels, leading to greater glucose uptake by muscles. [3]
This may include keeping certain biomolecules within a region, or keeping other molecules outside. Within the membrane-bound compartments, different intracellular pH, different enzyme systems, and other differences are isolated from other organelles and cytosol. With mitochondria, the cytosol has an oxidizing environment which converts NADH to ...
A classic example of a syncytium is the formation of skeletal muscle.Large skeletal muscle fibers form by the fusion of thousands of individual muscle cells. The multinucleated arrangement is important in pathologic states such as myopathy, where focal necrosis (death) of a portion of a skeletal muscle fiber does not result in necrosis of the adjacent sections of that same skeletal muscle ...
The sarcolemma (sarco (from sarx) from Greek; flesh, and lemma from Greek; sheath), also called the myolemma, is the cell membrane surrounding a skeletal muscle fibre or a cardiomyocyte. [ 1 ] [ 2 ] It consists of a lipid bilayer and a thin outer coat of polysaccharide material ( glycocalyx ) that contacts the basement membrane .
The fibres of striated muscle have a cylindrical shape with blunt ends, whereas those in smooth muscle are spindle-like with tapered ends. Striated muscle tissue has more mitochondria than smooth muscle. Both smooth muscle cells and cardiac muscle cells have a single nucleus, and skeletal muscle cells have many nuclei. [6]
The oxygen cascade is one system with clear limits, and can help determine the V o2max by components such as oxygen supply to the skeletal muscle mitochondria and the demand of oxygen by these skeletal muscle mitochondria. [7] If oxygen is not transferred via skeletal muscle mitochondria, it can then be transferred across muscle capillaries. [4]