Activity muscle

Sodium and Potassium. Whereas sodium ion is the most abundant cation in the extracellular fluid, potassium ion is the most abundant in the intracellular fluid. Small amounts of K" are requited in the extracellular fluid to maintain normal muscle activity. Some sodium ion is also present in intracellular fluid (see Fig. 5). Common food sources rich in potassium may be found in Table 7. Those rich in sodium are Hsted in Table 8. 

Measurement of muscle activity, usually measured by electrodes placed on the skin. The EMG is used in sleep research to aid in the discrimination of sleep stages, and also as part of diagnosis of sleep disorders such as periodic limb movements and restless legs syndrome. 

In a previous section we mentioned the significance of myosin filament structure. In nematodes two forms of myosin-II, myosin A and B, are required for proper filament stmcture (Epstein, 1988). The two forms of myosin are expressed at the proper time to allow for correct filament assembly. An accessory protein called paramyosin is also required for correct filament assembly. In vertebrate cardiac muscle, there are also two isoforms of myosin-II a-myosin and p-myosin. The proper ratio of these two proteins is of utmost importance for proper muscle activity. The incorrect synthesis of a- and P-myosins results in a severe cardiac disorder known as hypertrophic cardiomyopathy. Genetic transmission of the disease occurs in about 55% of families. The inherited condition is called familial hypertrophic cardiomyopathy (FHC), and this condition is a leading cause of sudden death in young athletes. 

Ruegg, J.C. (1988). Calcium in Muscle Activation. Springer-Verlag, Berlin. 

In any case, one might expect that the rate of the Ca -pump is rather slow relative to the processes unleashed by muscle activation. This is certainly tme for the Na -K -pump, and if it is tme for the Ca -pump as well, then the significance of the amount of charge which may or may not be transported concomitantly with Ca becomes rather unimportant. In short, the rate at which the pump works is more important for contraction than the detailed energetics of the transport reaction. How much of the variability of smooth muscle responsivity is in fact determined by transients in the Ca distribution, e.g., in smooth muscle myocytes, remains to be discovered. 

Muscle activity is accompanied by cellular pumping of sodium ions. The energy requirements of the sodium pump have been studied on an individual cardiac muscle mounted inside a tiny differential calorimeter and stimulated by electrical impulses. The heat evolved was different in the presence and absence of a known inhibitor of the sodium pump. 

Explain how blood volume, sympathetic stimulation of the veins, skeletal muscle activity, and respiratory activity influence venous return... 

Skeletal muscle activity. In the extremities (arms and legs), many veins lie between the skeletal muscles. Contraction of these muscles causes compression of the veins and an increase in venous pressure. This external... 

Baroreceptors are sensitive to changes in MAP. As VR, CO, and MAP decrease, baroreceptor excitation is diminished. Consequently, the frequency of nerve impulses transmitted from these receptors to the vasomotor center in the brainstem is reduced. This elicits a reflex that will increase HR, increase contractility of the heart, and cause vasoconstriction of arterioles and veins. The increase in CO and TPR effectively increases MAP and therefore cerebral blood flow. Constriction of the veins assists in forcing blood toward the heart and enhances venous return. Skeletal muscle activity associated with simply walking decreases venous pressure in the lower extremities significantly. Contraction of the skeletal muscles in the legs compresses the veins and blood is forced toward the heart. 

Bitwise D., Rye D., He L., Ansari F. (2003). Influence of PLMs on scoring phasic leg muscle activity. Sleep 26, A344. 

Isotonic muscle contraction was used to measure the effects of selected nematode FaRPs on the body-wall muscle of H. contortus. AF2 was found to have inhibitory effects on muscle activity and inhibited acetylcholine (ACh) -induced contractions in the worm whereas AF8 had excitatory effects on the muscle and enhanced ACh-induced contractions (Marks et al., 1999a). There were obvious differences in the methodologies used to evaluate the effects of these peptides on Haemonchus muscle compared with those used to examine these peptide effects on Ascaris. How comparable the results are has yet to be determined. 

Calcium 3.6 x 104 4.1 x lO-2 Second messenger, muscle activation, biominerals... 

Creatinine phosphate (CP + ADP —> creatinine + ATP) AMP Dissolved 02 Inorganic pyrophosphate Energy reservoir for muscle activity Mediator of hormone activity Measurement of water quality Medical Starting material for several biological compounds... 

Walker JW, Somlyo AV, Goldman YE, Somlyo AP, Trentham DR 1987 Kinetics of smooth and skeletal muscle activation by laser pulse photolysis of caged inositol 1,4,5-trisphosphate. Nature 327 249-251... 

During periods of acute psychosis, some patients exhibit so much muscular activity that they develop muscular destruction with the muscle product myoglobin in urine, which produces acute renal failure (16). Some muscle destruction may be due to involuntary muscle activity induced by the drug, while some may be due to the struggles of the agitated patient. In the latter case, the use of restraints may worsen the situation. 

Ataxia An inability to coordinate muscle activity during voluntary movement, so that smooth movements occur. Most often due to disorders of the cerebellum or the posterior columns of the spinal cord may involve the limbs, head, or trunk. 

Calcium, a crucial second messenger signalling key changes in cellular metabolism, is also important in muscle activation, in the activation of many proteases, both intra- and extracellular, and as a major component of an range of biominerals, including bone. 

Rarely seen. The Petco2 rises rapidly such that there may be a noticeable increase from breath to breath. The excess C02 is generated from the increased skeletal muscle activity and metabolic rate, which is a feature of the condition. 

O Lactic acid, CH3CHOHCOOH, is a monoprotic acid that is produced by muscle activity. It is also produced from milk by the action of bacteria. What is the pH of a 0.12 mol/L solution of lactic acid ... 

Table 3.8. RECEPTOR BINDING AND SMOOTH MUSCLE ACTIVITY OF CYCLIC DYNORPHIN DERIVATIVES [95]...

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