Перечень практических умений по изучаемой теме. 2. Владеть навыками изучающего чтения, извлекая необходимую информацию.

1. Владеть навыками монологической и диалогической речи, использовать новую лексику, уметь вести беседу по изучаемой теме.

2. Владеть навыками изучающего чтения, извлекая необходимую информацию.

3. Владеть навыками написания аннотации.

Рекомендации по выполнению НИРС .

1. “The Blood Circulation”

2. “Network of blood vessels”.

 

Приложение 1

Cardiovascular system, comprising both the heart and the blood vessels, circulates blood throughout the body. It carries essential supplies of food and fuel to every liv­ing cell and exchanges them for poten­tially harmful waste products. The adult circulation consists of thousands of mites of tubing containing about 10 pints (4.7l) of blood. The blood is kept flowing round the body by the pump­ing action of the heart.

Blood is made up of a pale yellow liquid (plasma) containing dissolved nutrients and wastes, plus blood cells, hormones, proteins and other sub­stances. Must numerous of these cells are the disk-shaped red blood cells. Their color comes from the presence of the substance hemoglobin, which com­bines with oxygen. When red corpuscles changed with oxygen approach body cells, the oxygen is delivered in exchange for the waste product carbon dioxide. Other two-way transportation of materials takes place between the body cells and the plasma, and all un­wanted substances are carried away in the blood for excretion by the kidneys, lungs, and liver. Plasma also contains white blood cells, which help to fight infection, and platelets, which are in­volved in blood clotting.

In its passage through the body, blood is carried in tubes known as ar­teries and veins. Most arteries transport oxygen-rich (oxygenated) blood, whereas most veins transport carbon dioxide-rich (deoxygenated) blood. The largest artery is the aorta, which stems directly from the heart. The aorta and other large arteries have thick walls lined with muscle. Blood flow is assisted by the contraction of this muscle and the impetus given by the heartbeat. The "push" from the heart can be felt as the pulse wherever large arteries run near the body surface.

As they penetrate the tissues, arteries split into narrow branches called arterioles, which in turn divide into capillar­ies. It is through the very thin capillary walls that the blood gives up its oxygen and nutrients and receives carbon dioxide and wastes. Deoxygenated blood in the capillaries flows into narrow veins (venules) and then into veins. The two largest veins, the venae cavae. return this blood to the heart. Veins have thin walls compared with those of arteries, and blood moves through the veins much more slowly. Blood flow in the veins is assisted by the action of mus­cles in surrounding tissues, and back-flow is prevented by one-way valves.

The deoxygenated blood delivered to the heart along the veins is no use to body calls until it has been recharged with oxygen. To ensure reoxygenation, the circulation has a second "loop." In this part of the system, blood rich in carbon dioxide travels from the heart along the pulmonary artery to the lungs, where carbon dioxide is ex­changed for oxygen breathed in. The pulmonary artery is the only artery to carry deoxygenated blood. The newly oxygenated blood is carried back to the heart along the pulmonary vein, the only vein to transport oxygenated blood.

 

Приложение 2

The Human Heart

The heart is a muscular organ about the size of a clenched fist. The struc­ture and action of the heart are de­signed to serve the two loops of the cir­culation. Inside, the heart is divided vertically by a muscular wall. On each side of this wall Is an upper chamber (atrium) and a thicker, lower chamber (ventricle). Blood moves through each side of the heart systematically. Deoxy­genated blood is delivered into the right atrium. It then enters the right ventricle, from where it is pumped out into the pulmonary artery and to the lungs. Oxygenated blood returning in the pulmonary veins flows into the left atrium. This blood enters the left ven­tricle and is then pumped into the aorta for circulation.

The flow of blood in each side of the heart is controlled by a series of valves. The pumping action of the heart is achieved by the contraction of the car­diac muscle, of which the heart is largely composed. The rhythm of the heartbeat is regulated by bursts of elec­trical impulses sent out by a concentra­tion of specialized heart tissue called the pacemaker.

Under the influence of the pace­maker, the heart of an adult at rest beets at a rate of 60 to 80 beats a min­ute. The pacemaker also helps to ensure the correct sequence of activities during each heartbeat; first the two atria contract, followed rapidly by the ventricles. The powerful contraction of the ventricles pushes blood into the aorta and pulmonary artery. This pe­riod of contraction (systole) is followed by a period of relaxation (diastole), during which the heart refills. The complete sequence is accompanied by electrical activity of the muscle, which can be monitored as an electrocardi­ogram (EKC).

 

Приложение 3

Angina Pectoris

Angina pectoris is chest pain or discomfort that occurs when your heart muscle does not get enough blood. Angina may feel like pressure or a squeezing pain in your chest. The pain may also occur in your shoulders, arms, neck, jaw, or back. It may also feel like indigestion.

Angina is a symptom of coronary artery disease (CAD), the most common type of heart disease. CAD occurs when plaque builds up in the coronary arteries. This buildup of plaque is called atherosclerosis. As plaque builds up, the coronary arteries become narrow and stiff. Blood flow to the heart is reduced. This decreases the oxygen supply to the heart muscle.

Types of Angina

The three types of angina are stable, unstable, and variant. It is very important to know the differences among the types.

• Stable angina. Stable angina is the most common type. It occurs when the heart is working harder than usual.
• There is a regular pattern to stable angina. After several episodes, you learn to recognize the pattern and can predict when it will occur.
• The pain usually goes away in a few minutes after you rest or take your angina medicine.
• Stable angina is not a heart attack but makes it more likely that you will have a heart attack in the future.
• Unstable angina. Unstable angina is a very dangerous condition that requires emergency treatment. It is a sign that a heart attack could occur soon. Unlike stable angina, it does not follow a pattern. It can occur without physical exertion and is not relieved by rest or medicine.
• Variant angina. Variant angina is rare. It usually occurs at rest. The pain can be severe and usually occurs between midnight and early morning. It is relieved by medicine.

What Causes Angina?

Angina is caused by reduced blood flow to an area of the heart. This is most often due to coronary artery disease (CAD). Sometimes, other types of heart disease or uncontrolled high blood pressure can cause angina.

In CAD, the coronary arteries that carry oxygen-rich blood to the heart muscle are narrowed due to the buildup of fatty deposits called plaque. This is called atherosclerosis. Some plaque is hard and stable and leads to narrowed and hardened arteries. Other plaque is soft and is more likely to break open and cause blood clots. The buildup of plaque on the inner walls of the arteries can cause angina in two ways: by narrowing the artery to the point where the flow of blood is greatly reduced and by forming blood clots that partially or totally block the artery.

The illustration shows a normal artery with normal blood flow (Figure A) and an artery containing plaque buildup (Figure B).

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