Skeletal myocyte

FIGURE 43-4 Cellular and molecular organization of the skeletal myocyte. 

Nicotinic receptors (skeletal myocyte, Sympathetic and parasympathetic gangJia ... 

Skeletal muscle cells are capable of regeneration and repair more readily than cardiac myocytes owing to the so-called satellite cells that can be readily mobilized at the time of injury (16). They are capable of easy expansion in culture can be harvested easily from the autologous host and are fairly resistant to hypoxia (17). The major drawback is that as the skeletal myocytes mature, they no longer form gap junctions and become electrically isolated, predisposing to re-entry arrhythmias (18). In addition, despite some encouraging data (19), the viability of dissociated myoblasts in suspension injected into myocardial scar deprived of appropriate trophic environment has been called into question (20), In our hands, skeletal myoblasts injected into canine myocardium could not be identified four weeks after implantation, and the needle tract caused fibrosis and scarring (Fig. 2). 

Fig. 11-4 Overview of giucose uptake and disposal in skeletal myocytes and adipocytes. Giucose enters the ceil via GLUT-1 and via the insulin-stimulated insertion of GLUT-4 carriers into the plasma membrane. Glucose 6-phosphate is a point of flux divergence into glycolysis and glycogen synthesis.

Fuel is stored primarily as droplets of triglyceride in adipocytes, and as glycogen particles in both hepato-cytes and skeletal myocytes other tissues have little fuel storage capacity and primarily rely on a continuous supply of fuel from the liver via the bloodstream. 

In conclusion, fatty acid oxidation inhibits glucose oxidation and provides acetyl-CoA to the Krebs cycle it also ensures that any glucose that enters skeletal myocytes is not rapidly oxidized, but is converted into lactate that leaves the cells and is transported in the hlood to hepatocytes and cardiac myocytes. Although this conservation of glucose occurs in skeletal myocytes and other tissues, it does not occur in the brain because fatty acids do not cross the blood-brain barrier. Thus even after 2 days of starvation, the brain continues to use -120 g of glucose per day. 

How does a rise in fatty acid concentration in the blood lead to the stimulation of fatty acid oxidation in skeletal myocytes ... 

Is the conversion of oxaloacetate to phosphoenol pyruvate more likely to occur in the mitochondria or the cytoplasm of skeletal myocytes, and or hepatocytes ... 

Korcok, J. Dixon, S. J. Lo, T. C. Y. Wilson, J. X. 2003. Differential effects of glucose on debydroascorbic acid transport and intracellular ascorbate accumulation in astrocytes and skeletal myocytes. Brain Res. 993 201-207. 

Collinsworth, A. M., C. E. Torgan, S. N. Nagda et al. 2000. Orientation and length of mammalian skeletal myocytes in response to a unidirectional stretch. Cell Tissue Res 302(2) 243-51. 

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