Зоология на английском. Обязательный материал для чтения на занятиях и дома. Сологуб Л.И. - 42 стр.

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Text 25
I. Read the text and say what information it carries.
CIRCULATIOH
In the Protozoa and many of the lowest Metazoa, the transport of materials
to and from the various parts of the organism is obviously a simple problem
compared to that presented by animals with deeply-hidden tissues, each and
every cell of which must be served. Indeed a complex body is impossible
without a complex circulatory system.
The crucial points of contact between the higher animal and its
environment, in so far as the intake of matter and energy is concerned, are the
membranes which line the digestive tract and the lungs. Through the former
must pass all the materials which are to be assembled as internal parts of the
organism and the fuel which is to supply the energy for the vital processes,
while through the latter must pass the oxygen which is to realize this energy.
Only when these membranes have been passed, are the materials really within
the body and at its disposal for distribution by the circulatory system to the
individual cells of the various organs which are to use them.
In addition to carrying the fuel and the oxygen the circulatory system must
remove the waste products of metabolism from the cells and deliver them to the
proper excretory organs, such as the lungs or kidneys to be passed to the outside
world. The circulatory system is, therefore, the essential connecting link
between the points of intake, utilization, and outgo of materials. The circulatory
system is also a coordinating agent of crucial importance, because it distributes
complex chemical substances, known as hormones, from their specific points of
origin in the various endocrine glands to the particular tissue or organ where
their regulatory influence is to be effected. So the circulatory system is a
distributing system which not only maintains a suitable environment for the
myriads of cells of the body, but also, in cooperation with the nervous system,
unifies the organs Into an organism.
II. Remember the following words, consult a dictionary about the way they are
pronounced:
circulation циркуляция
protozoa протозоа
circulatory циркулирующий
fuel топливо, горючее
vital жизненный
excretory выводной, выделительный
hormone гормон
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