During effort coronary flow increase considerably whereas myocardial oxygen e traction remains largely the same as at rest. Aortic pressure plays a major role in regulating coronary circulation. The patient in a state of cardiac insufficiency is not capable increase his cardiac work to the same degree. The result is a reduction in contractility. The defective heart does not fully utilize the energy obtained from glucose degradation. The result is a reduction in cardiac output.
The predominant symptom is dyspnoea, which results from the increase in respiratory work. Due to reduced cardiac output, fatigue, gastrointestinal disorders and renal dysfunction take puce. This affects the normal functioning of the various organs. There is about skeletal muscles body. Many consists of bundles of muscle which is wrapped — as is the total mi connective tissue in which nerves and blood are embedded.
The tissues combine to form that connect ends of the muscle to bones active action a muscle can do is to contract by filaments. Elongation is brought about forces. This is a complex phenomenon involving many internal human reactions. Muscle fibers cells are controlled by a single motor nerve fiber.
This is known as the motor unit. An impulse started in a motor nerve cell motoneuron propagates along the nerve fiber and transmitted to the motor endplate ate where acetyl chlorine is released. This reverses the resting membrane potential. The neuromuscular transmission transducers electrical signals nerve impulses to chemical signals and then back to electrical signals muscle action potentials.
This initiates the mechanical-chemical mechanisms and causes the muscle to react. In the activated muscle, the contractile components myofibrils , shorten and stretch the elastic components connective tissue, tendon.
When no movement, the contraction is called isometric static and when the muscle is activated to vary its length, the contraction is isotonic dynamic. In the latter case, external work can be given by the following equation-. During works performance, a part of mechanical efficiency is dissipated as heat.
Thus muscle activation increases heat production which causes perspiration. To prevent overheating during prolonged muscular activity increased local blood flow and increased heat conductance of skin are essential.
During muscular work physiological functions change from the resting level and heart rate, blood pressure, cardiac output, respiration, pulmonary ventilation, oxygen uptake, carbon dioxide production, chemical composition of blood and urine, body temperature, rate of perspiration, etc. They come back to resting level when the works stop. By measuring one or more physiological variables during activity it is possible to determine what degree the working level differs from the resting level.
This gives an estimate of the physiological stress experienced in performing a given task. When the activity ceases it is possible to follow the return of the same variables to the resting level and to determine the duration of the recovery period at the end of which the individual has returned to his pre-activity physiological equilibrium.
In order to evaluate total physiological expenditure, one must consider physiological reaction both during the work and during the recovery period.
A complete work cycle includes the physiological cost of work plus the physiological cost of recovery. Environmental factors that affect are heat, cold, noise, vibration, gas pressure, altitude, air pollution etc. Nature of work can also affect. It includes intensity, duration, technique, position, and rhythm.
All the above factors — food and nutritional, physiological, environmental, psychic and nature of work actuate service functions that deliver fuel and oxygen to the working muscle fiber.
This service function capacity transforms food energy chemically bound into mechanical energy for muscular work. This ability of the muscle cell to transform energy actuates ability to perform physical work. Therefore by paying attention on above factors i. The rate of heat removal, CO2, Water, waste products etc.
To maintain the physical and chemical equilibrium of the cells, a tremendous increase in the exchange of molecules between intra and extracellular fluid is required. Search the web. Citation Use the citation options below to add these abbreviations to your bibliography. Powered by CITE. A Non-Elderly Dementia. Activities for Non Elderly Dementia.
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