Глубина по времени отзвука

XII. 1. Прочтите текст С. 2. Озаглавьте его. 3. Найдите предложения с подлежащим, выраженным словом 'one'. 4. Переведите эти предложения. 5. Выпишите английские эквиваленты следующих словосочетаний:

1. для этой цели; 2. полный покой; 3. распространяется по коре головного мозга; 4. имеет большое защитное значение для; 5. глубокий спокойный сон; 6. жизнедеятельность

Text С

The nervous cells of the cortex are the most delicate of all the cells of the human body.

It is at the moment of tiredness of the cortical nervous cells that the process of inhibition begins to act. This process does not allow new stimuli to pass to the tired areas of the brain. To provide the smooth work of the brain the nervous cells must be well supplied with oxygen and feeding substances. And for this purpose any human being must have regular complete rest, i.e. sleep.

When the process of inhibition extends over a great number of cells, spreads widely over the cortex and even over the subcortical areas of the brain one falls asleep.

When one sleeps the vital activity of the nervous system is restored. So sleep is of a great protective significance to the human being.

The man sleeps about one third of his life. Numerous investigations and experiments have shown that sleep is more necessary for the human being than food. One can live longer without food than without sleep.

During a sound quiet sleep the whole activity of the human organism changes, the body metabolism decreases, the respiratory and pulse rates become slower, the body temperature drops. Though the stimuli continue to come into the brain, the inhibited cortical cells do not react to them. 124