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Work of the Human Heart

Exercise 4. I. Form adjectives from the verbs using the suffix -able (-ible).Translate them.

а) Drink, separate, break, change, eat, read, recognize, work, fashion, understand, count, teach, comfort

b) cure, move, observe, prevent, use, tolerate, consider, response, notice, depend, control

II. Form verbs with the help of the suffix -ate. Translate into your native language.

- ate: vaccine, saliva, origin, suffocation, regulation, separation, circulation

Exercise 5. Translate into your native language. Pay attention to the use of the Perfect Tense:

1. I have never been to Great Britain.
2. The scientist has already finished the experiment.
3. The doctor has not discharged the patient from the clinic yet.
4. My sister’s health hasn’t changed since she was discharged from the hospital.
5. Have you ever performed any operation?
6. The nurse has just determined the patient’s blood group.
7. The doctor has performed a lot of operations lately.
8. The patient has lost 3 kilograms of weight this month.

Exercise 6. Read and translate the 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 fibers. It varies in different persons and at different age.

Physiologists have determined that in the adult the heart makes from 60 to 72 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: physiolo­gists have called the first phase of short contraction of both atria —the atrial systole. They have called 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.

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