Muscular Activity

The human body has more than 600 muscles. The body s movement is performed by muscle contractions, which are stimulated by the nervous system. This system links muscle tissue to the spinal cord and brain. The network of nerve cells which carries the brain s signals directs the flow of muscular energy. Most muscular activity occurs beyond the range of the conscious mind. The body, working through the neuromuscular network, manages... 

Lactic acid, QH C, is a weak organic acid present in both sour milk and buttermilk. It is also a product of carbohydrate metabolism and is found in the blood after vigorous muscular activity. A buffer is prepared by dissolving lactic acid, HLac (ffa = 1.4 X 10-4), and sodium lactate, NaC3H503, NaLac. Calculate [H+] and the pH of the buffer if it is made of... 

The process by which yeast breaks down glucose has been carefully studied by biochemists and the way in which this transformation occurs is now known in considerable detail. One of the reasons this process is so interesting is that a nearly identical process takes place in human muscle, in this case to furnish energy needed for muscular activity. 

Table 8 5 shows that each of the four common s-block ions is abundant not only in seawater but also in body fluids, where these ions play essential biochemical roles. Sodium is the most abundant cation in fluids that are outside of cells, and proper functioning of body cells requires that sodium concentrations be maintained within a narrow range. One of the main functions of the kidneys is to control the excretion of sodium. Whereas sodium cations are abundant in the fluids outside of cells, potassium cations are the most abundant ions in the fluids inside cells. The difference in ion concentration across cell walls is responsible for the generation of nerve impulses that drive muscle contraction. If the difference in potassium ion concentration across cell walls deteriorates, muscular activity, including the regular muscle contractions of the heart, can be seriously disrupted. 

Manometry Measurement of pressures within organs of the body. Manometry is often used to indicate muscular activity in motile tubes such as the esophagus. 

Drugs that affect tissue properties, particularly blood flow at the absorption site, may be used to control the rate of absorption. Reduced drug absorption may be achieved physiologically with an IM preparation by incorporating epinephrine, which causes a local constriction of blood vessels at the site of injection. Increased muscular activity may enhance drug absorption because of increased drug flow. 

Regulates muscular activity and glandular secretion responsible for all activities associated with the mind... 

Muscular activity, or gastrointestinal motility, is enhanced by stretching the muscle, as occurs with the presence of food materials and distension of... 

Segmentation contractions occur as a result of the basic electrical rhythm (BER) of pacemaker cells in the small intestine. This form of muscular activity is slight or absent between meals. The motility of the small intestine may be enhanced during a meal by ... 

Numbness and tingling of the limbs, twitching of the facial muscles, inability to coordinate muscular activity, nausea, visual hallucinations, and a deep stupor are characteristic. Macroscopia is frequent, entering into Waika belief about the spirits that dwell within the plant. Levitation, or a sensation of floating in air or flying, is reported. 

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. 

Classic beri-beri, rarely seen in the United States and Europe, except in alcoholism (P4), is endemic in the Far East because of the prevalent diet of decorticated rice (F6). It occurs in two forms wet beri-beri, characterized by edema and cardiovascular symptoms (G6), and dry beri-beri with peripheral neuritis, paralysis, and atrophy of the muscles. Conditions which may predispose to deficiency by increasing thiamine requirements are pregnancy (see section 2.4), and lactation, hyperthyroidism, malignant disease, febrile conditions, increased muscular activity, high carbohydrate diets, and parenteral administration of glucose solutions. A constant supply of thiamine is required for optimal nutrition because storage in the liver and elsewhere is limited. Thiamine is synthesized by bacteria in the intestinal tract of various animals, but this is not a dependable source for man. 

Hill, A.V. (1926). Muscular Activity. Williams Wilkins, Baltimore. 

However, it should be noted that although fat oxidation provides quantitatively more ATP than does the oxidation of glucose, the rate at which ATP is generated via 13-oxidation is slower than the rate of generation by glycolysis a fact which explains why glucose is the preferred fuel during sudden bursts of muscular activity when ATP concentration need to be topped-up rapidly. 

The oral temperature is the resultant, for that region, of all the heat-producing and heat-dissipating agencies in the entire body and is, thus, an attempted summation. Since biochemical activity is accompanied by increased heat production, local activities tend to produce local temperature rises. Blood flow, of course, tends constantly to diminish any differentials which are built up by local activity. Muscular activity may, partly because muscle is so abundant, increase the temperature of the whole body until there is a high fever of 103°F. or more. 

Muscular activity effects the concentration of many biochemical constituents. Mild exercise, walking at a rate of 5.6 km/hour produced a 20% increase in creatine clearance (Kl). However, severe exercise (jogging at 10.5 km/hr) produced a 40% decrease in clearance (Kl). Mild exercise (a 3-hour march) produced a mean fall of 18.2 mg/100 ml in haptoglobin levels from pre-exercise concentrations of 84.5 mg/100 ml (H14). Similar observations have been made for thyroxine and hormonebinding proteins (D7). 

Gll. Griffiths, P. D., Serum levels of CPK. The normal range and effect of muscular activity. Clin. Chim. Acta 13, 413-420 (1966). 

Diethylcarbamazine is a derivative of piperazine. The mechanism of its action is not completely understood. However, it is highly likely that it causes a reduction in muscular activity, and even paralysis in hehninthes. It quickly gets rid of the parasites Brugia malayi, Loa loa, and Wuchereria bancrofti, and it is also used for diseases caused by Onchocerca volvulus and Mansonella strptocerca. Synonyms of this drug are hetrazan, notezine, banoside, and others. 

CFS patients and is related to autonomic dysfunction. In a separate rat study, Giannesini et al. used citrulline malate (CM) to treat asthenia and found that the supplementation prevented the basal PCr/ATP ratio reduction and normalized the pHi time-course during muscular activ-ity. They conclude that CM supplementation corrects the impaired control of oxidative function and has protective effect on basal energy metabolism. The data from either human or animal studies provide a potential approach to therapy. 

For many drugs, at least part of the toxic effect may be different from the therapeutic action. For example, intoxication with drugs that have atropine-like effects (eg, tricyclic antidepressants) reduces sweating, making it more difficult to dissipate heat. In tricyclic antidepressant intoxication, there may also be increased muscular activity or seizures the body s production of heat is thus enhanced, and lethal hyperpyrexia may result. Overdoses of drugs that depress the cardiovascular system, eg, 13 blockers or calcium channel blockers, can profoundly alter not only cardiac function but all functions that are dependent on blood flow. These include renal and hepatic elimination of the toxin and any other drugs that may be given. 

The lactate formed by active skeletal muscles (or by erythrocytes) can be recycled it is carried in the blood to the liver, where it is converted to glucose during the recovery from strenuous muscular activity. When lactate is produced in large quantities during vigorous muscle contraction (during a sprint, for example), the acidification that results from ionization of lactic acid in muscle and blood limits the period of vigorous activity. The best-conditioned athletes can sprint at top speed for no more than a minute (Box 14-1). 

Other large animals, such as the elephant and rhinoceros, have similar metabolic characteristics, as do diving mammals such as whales and seals. Dinosaurs and other huge, now-extinct animals probably had to depend on lactic acid fermentation to supply energy for muscular activity, followed by very long recovery periods during which they were vulnerable to attack by smaller predators better able to use oxygen and thus better adapted to continuous, sustained muscular activity. 

Skeletal muscle can use free fatty acids, ketone bodies, or glucose as fuel, depending on the degree of muscular activity (Fig. 23-17). In resting muscle, the primary fuels are free fatty acids from adipose tissue and... 

After a period of intense muscular activity, the individual continues breathing heavily for some time, using much of the extra 02 for oxidative phosphorylation in the liver. The ATP produced is used for gluconeogenesis from lactate that has been carried in the blood from the muscles. The glucose thus formed returns to the muscles to replenish their glycogen, completing the Cori cycle (Fig. 23-18 see also Box 15-1). 

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