I. Exercises.

ex. 1 Memorize the pronunciation of the following words:

total cardiac

ton systole

emotion diastole

regulate cadiovascular

ex. 2 Memorize the meaning of the following words:

pump - накачивать, нагнетать per - в, на, за

rate - частота, скорость per minute - в минуту

pulse rate - частота пульса depend (on, upon) - зависеть (от)

respiratory rate - частота дыхания wave - волна, колебание

beat (n) - толчок, удар, биение follow - следовать, соблюдать

beat (v) — бить(ся)б ударять(ся) exertion — напряжение, нагрузка

prolong (v) - продлевать on exertion - при напряжении (нагрузке)

prolonged - длительный estimate - определять, подсчитывать

discharge - выделять serve - служить

discharge from - выписывать send (sent, sent) - посылать, направлять

discharge out - выбрасывать considerable - значительный

ex. 3 Translate the word combinations:

on physical exertion, to be discharge from the hospital, to discharge out some blood, pulmonary circulation, to estimate the number of cells, to pump blood through the blood vessels, the total body weight, the period of rest, much higher

ex. 4 Translate into English:

1. чувствовать боль при физическом напряжении; to feel pain on physical exertion; 2. иногда физическое напряжение вызывает боль; sometimes physical exertion causes pain; 3. выбрасывать (выталкивать) кровь; to discharge out some blood; 4. она выписалась из больницы; she is discharged from the hospital; 5. малый круг кровообращения; pulmonary circulation; 6. большой круг кровообращения; systemic circulation; 7. периферическое кровообращение; peripheral circulation; 8. определят роль желудочков; to estimate the role of the ventricles; 9. медсестра подсчитала число клеток крови; the nurse has estimated the number of blood cells; 10. изменения зубцов электрокардиограммы зависят

от состояния работы сердца; the changes of the electrocardiogram waves depend on the condition of the heart activity

II. Text "Work of the Human Heart"

The human heart contracts from the first moment of life until the last one. The contractions of the heart pump the blood through the arteries to all the parts of the body. Scientists have determined that the total weight of the blood pumped by the heart daily is about ten tons.

The rate of heart contractions is regulated by two groups of nerve fibres. It varies in different persons and at different age.

Physiologists have determined that in the adult the heart makes from 60 to72 beats per minute. In children the rate of heartbeat is much higher. Research work of many scientists has helped to determine that the rate of heartbeat increases depending on different emotions.

Each beat of the heart is followed by a period of rest for the cardiac muscle. Each wave of contraction and a period of rest following it compose a cardiac cycle.

Research work has given physiologists the possibility to find out that the heart muscle works or contracts about one third of the time of the person's life. The period of rest is shorter during greater physical exertion and longer when the body is at rest.

Each cardiac cycle consists of three phases: the first phase of short contraction of both atria - the atrial systole; the second phase of a more prolonged contraction of both ventricles - the ventricular systole. The period of rest of the cardiac muscle is called the diastole.

The left ventricle discharges out the blood received by the left atrium from the pulmonary circulation through the aorta to the systemic circulation.

The blood received from the systemic circulation by the right atrium is discharged out of the right ventricle to the lungs through the pulmonary arteries.

Prolonged research work of many physiologists has given the possibility to estimate the role of the ventricles which serve as the main pump. The atria act as receiving chambers. The contraction of the atria which sends the final portion of the blood into the ventricle is considerably less.