Circulation
Circulation is a process during which the substances move in the body of an organism.
Single-celled organisms use cytoplasm which moves from one part of the organism to another and brings the nutrients to different parts of the organism.
Multicellular organisms use cell walls between the cells to transport water and mineral substances from one cell to another.
Plants use conductive tissues to transfer nutrients. The tissues make a vascular system in the shoots, roots, flowers and fruits. Water and minerals move in the xylem vessels and organic substances in the phloem vessels.
Multicellular animals have a circulatory system which consists of vessels and the heart. Blood circulates in the vessels. The vessels fall into arteries and veins. Arteries take blood from the heart. Veins bring blood to the heart. The body has a lot of capillaries which exchange blood in the tissues. Blood brings nutrients and oxygen to all parts of the organism and takes away carbon dioxide and other products of the breakup. Blood consists of plasma and blood cells. Red blood cells give the red colour because they have a red pigment – hemoglobin. Hemoglobin brings oxygen to the organism. White blood cells protect the organism: they destroy disease-causing organisms (parasites). Blood circulation is stimulated by heart muscle contraction. The heart has chambers – ventricles and atriums. Blood from the veins comes into the atrium and then goes to the ventricle. When the ventricle contracts, it pushes blood into the arteries which send blood with oxygen and nutrients all over the body. The blood circulatory system is secluded. Birds and mammals have a 4-chambered heart.
Circulation of water in plants is provided by root pressure and evaporation of water from the surface of the leaves. This process provides the plants with the constant rising water current all over the plant: the plants loses water due to evaporation and absorbs water from the soil through roots.
Circulation – транспорт веществ в организме
Cytoplasm – цитоплазма
Nutrients – пит. вещества
A cell wall – клеточная стенка
To transport = to transfer – транспортировать
Conductive tissue – проводящая ткань
A vascular system – сосудистая система
A shoot – побег
A root – корень
A fruit – плод
Xylem – древесина, ксилема
A vessel – сосуд
Phloem – луб, флоэма
A circulatory system – система перемещения веществ
To circulate – вращаться
To fall into – распадаться на
An artery – артерия
A vein – вена
To take … from – забирать
A capillary – капилляр
To exchange – обмениваться
To take away – забирать
Carbon dioxide – углекислый газ
Products of breakup – продукты распада
Red blood cells – красные кровеносные тельца
Hemoglobin – гемоглобин
White blood cells – белые кровеносные тельца
Disease-causing – болезнетворный
Muscle contraction – сокращение мускулов
A chamber – камера
A ventricle – желудочек
An atrium – предсердие
To contract – сокращаться
To push … into – выталкивать
All over the body – по всему телу
Secluded blood circulatory system – замкнутая кровеносная система
A mammal – млекопитающее
A 4-chambered heart – четырехкамерное сердце
To provide – снабжать
Root pressure – корневое давление
Evaporation of water – испарение воды
The surface of the leaves – поверхность листьев
Constant – постоянный
Rising water current – восходящий ток воды
To lose water – терять воду
Due to – из-за
To absorb water – поглощать воду