Phần 1: Giải phẫu và sinh lý tim
Bài 1: Dịch các từ có đánh số trong hình dưới sang tiếng Việt 1-19
Bài 2: Dịch sang tiếng Việt các đoạn sau:
The heart is a muscular pump that propels blood to entire body through a closed vascular system. It is found in a sac called the pericardium. The heart is composed of three distinct tissue layers:
• endocardium, a serous membrane that lines the four chambers of the heart and its valves and is continuous with the endothelium of the arteries and veins
• myocardium, the muscular layer of the heart
• epicardium, the outermost layer of the heart.
The heart is divided into four chambers. The two upper chambers, the right atrium and left atrium, collect blood. The two lower chambers, the right ventricle and left ventricle, pump blood from the heart. The right ventricle pumps blood to the lungs (pulmonary circulation) for oxygenation, and the left ventricle pumps oxygenated blood to the entire body(systemic circulation).
Deoxygenated blood from the body returns to the right atrium by way of two large veins: the superior vena cava, which collects and carries blood from the upper body; and the inferior vena cava, which collects and carries blood from the lower body. From the right atrium, blood passes through the tricuspid valve, consisting of three leaflets, to the right ventricle.When the heart contracts, blood leaves the right ventricle by way of the left pulmonary artery and right pulmonary artery and travels to the lungs.During contraction of the ventricle, the tricuspid valve closes to prevent a backflow of blood to the right atrium.The pulmonic valve(or pulmonary semilunar valve)prevents regurgitation of blood into the right ventricle from the pulmonary artery. In the lungs, the pulmonary artery branches into millions of capillaries, each lying close to an alveolus. Here, carbon dioxide in the blood is exchanged for oxygen that has been drawn into the lungs during inhalation.
Pulmonary capillaries unite to form four pulmonary veins,two right pulmonary veins and two left pulmonary veins. These vessels carry oxygenated blood back to the heart. They deposit blood in the left atrium. From there, blood passes through the mitral(bicuspid)valve,consisting of two leaflets to the left ventricle. Upon contraction of the ventricles, the oxygenated blood leaves the left ventricle through the largest artery of the body, the aorta. The aorta contains the aortic semilunar valve (aortic valve)that permits blood to flow in only one direction from the left ventricle to the aorta. The aorta branches into many smaller arteries that carry blood to all parts of the body. Some arteries derive their names from the organs or areas of the body they vascularize. For example, the splenic artery vascularizes the spleen and the renal arteries vascularize the kidneys. It is important to understand that oxygen in the blood passing through the chambers of the heart cannot be used by the myocardium as a source of oxygen and nutrients. Instead, an arterial system composed of the coronary arteries branches from the aorta and provides the heart with its own blood supply. The artery vascularizing the right side of the heart is the right coronary artery. The artery vascularizing the left side of the heart is the left coronary artery. The left coronary artery divides into the left anterior descending artery and the circumflex artery. If blood flow in the coronary arteries is diminished, damage to the heart muscle may result.When severe damage occurs, part of the heart muscle may die.
Conduction System of the Heart
Within the heart, a specialized cardiac tissue known as conduction tissue has the sole function of initiating and spreading contraction impulses. This tissue consists of four masses of highly specialized cells that possess characteristics of nervous and cardiac tissue:
• sinoatrial (SA) node
• atrioventricular (AV) node
• bundle of His (AV bundle)
• Purkinje fibers.
The sinoatrial (SA) node is located in the upper portion of the right atrium and possesses its own intrinsic rhythm. Without being stimulated by external nerves, it has the ability to initiate and propagate each heartbeat, thereby setting the basic pace for the cardiac rate. For this reason, the SA node is commonly known as the pacemaker of the heart. Cardiac rate may be altered by impulses from the autonomic nervous system. Such an arrangement allows outside influences to accelerate or decelerate heart rate. For example, the heart beats more quickly during physical exertion and more slowly during rest. Each electrical impulse discharged by the SA node is transmitted to the atrioventricular (AV) node, causing the atria to contract. The AV node is located at the base of the right atrium. From this point, a tract of conduction fibers called the bundle of His (AV bundle), composed of a right and left branch, relays the impulse to the Purkinje fibers. These fibers extend up the ventricle walls. The Purkinje fibers transmit the impulse to the right and left ventricles, causing them to contract. Blood is now forced from the heart through the pulmonary artery and aorta. Thus, the sequence of the four structures responsible for conduction of a contraction impulse is:
SA node →AV node →bundle of His →Purkinje fibers
Impulse transmission through the conduction system generates weak electrical currents that can be detected on the surface of the body. An instrument called an electrocardiograph records these electrical impulses, using a needle, or stylus, that records the activity on graph paper. The needle deflection of the electrocardiograph produces waves or peaks designated by the letters P,Q, R, S, and T, each of which is associated with a specific electrical event:
• The P wave is the depolarization (contraction) of the atria.
• The QRS complex is the depolarization (contraction) of the ventricles.
• The T wave, which appears a short time later, is the repolarization (recovery) of the ventricles.
Blood pressure (BP) measures the force of blood against the arterial walls during two phases of a heartbeat: the contraction phase (systole) when the blood is forced out of the heart, and the relaxation phase (diastole) when the ventricles are filling with blood. Systole produces the maximum force; diastole, the weakest. These measurements are recorded as two figures separated by a diagonal line. Systolic pressure is given first, followed by diastolic pressure. For instance, a blood pressure of 120/80 mm Hg means a systolic pressure of 120 with a diastolic pressure of 80. A consistently elevated blood pressure is called hypertension; decreased blood pressure is called hypotension.
Several factors influence blood pressure:
• resistance of blood flow in blood vessels
• pumping action of the heart
• viscosity, or thickness, of blood
• elasticity of arteries
• quantity of blood in the vascular system.
Phần 2: Các thuật ngữ và bệnh học cơ bản của tim mạch
Bài 1: Hãy đọc và dịch các thuật ngữ sau, một thuật ngữ lấy ít nhất 1 ví dụ
aneurysm/o: widened blood vessel
angi/o: vessel (usually blood or lymph)
ather/o: fatty plaque
embol/o: embolus (plug)
hemangi/o: blood vessel
scler/o: hardening; sclera (white of eye)
sten/o: narrowing, stricture
thromb/o: blood clot
ventricul/o: ventricle (of the heart or brain)
-gram: record, writing
-graph: instrument for recording
-graphy: process of recording
-stenosis: narrowing, stricture
endo-: in, within
Bài 2: Dịch sang tiếng Việt các đoạn sau
Arteriosclerosis is a hardening of arterial walls that causes them to become thickened and brittle. This hardening results from a build-up of a plaquelike substance composed of cholesterol, lipids, and cellular debris (atheroma).Over time, it builds up on the inside lining (tunica intima) of the arterial walls. Eventually, the plaque hardens (atherosclerosis), causing the vessel to lose elasticity(See Figure 1.) The lumen narrows as the plaque becomes larger. After a while, it becomes difficult for blood to pass through the blocked areas. Tissues distal to the occlusion become ischemic. In many instances, blood hemorrhages into the plaque and forms a clot (thrombus) that may dislodge. When a thrombus travels though the vascular system it is called an embolus (plural, emboli). Emboli in venous circulation may cause death. Emboli in arterial circulation commonly lodge in a capillary bed and cause localized tissue death (infarct). Sometimes plaque weakens the vessel wall to such an extent that it forms a bulge (aneurysm) that may rupture(See Figure 2.) Arteriosclerosis usually affects large or mediumsized arteries, including the abdominal aorta; the coronary, cerebral, and renal arteries; and major arteries of the legs (femoral arteries). One of the major risk factors for developing arteriosclerosis is an elevated cholesterol level (hypercholesterolemia). Other major risk factors include age, family history, smoking, hypertension, and diabetes. Treatment for arthrosclerosis varies depending on the location and symptoms. In one method, occluding material and plaque are removed from the innermost layer of the artery (endarterectomy).In this procedure, the surgeon opens the site and removes the plaque, thereby resuming normal blood flow. Physicians commonly use endarterectomy to treat carotid artery disease, peripheral arterial disease, and diseases of the renal artery and aortic arch.
Coronary Artery Disease
In order for the heart to function effectively, it must receive an uninterrupted supply of blood. This blood is delivered to the heart muscle by way of the coronary arteries. Failure of the coronary arteries to deliver an adequate supply of blood to the myocardium is called coronary artery disease (CAD). Its major cause is the accumulation of plaque which causes the walls of the artery to harden (arteriosclerosis). With partial occlusion, localized areas of the heart experience oxygen deficiency (ischemia). When the occlusion is total or almost total, the affected area of the heart muscle dies (infarction)(See Figure 3.) The clinical signs and symptoms of myocardial infarction (MI) typically include intense chest pain (angina), profuse sweating (diaphoresis), paleness (pallor), and labored breathing (dyspnea). Arrhythmia with an abnormally rapid heart rate (tachycardia) or an abnormally slow heart rate (bradycardia) may also accompany an MI. As the heart muscle undergoes necrotic changes, it releases several highly specific cardiac enzymes, including troponin T, troponin I, and creatinine kinase (CK). The rapid elevation of these enzymes at predictable times following MI helps differentiate MI from pericarditis, abdominal aortic aneurysm (AAA), and acute pulmonary embolism. When angina cannot be controlled with medication, surgical intervention may be necessary. In percutaneous transluminal coronary angioplasty (PTCA), a deflated balloon is passed through a small incision in the skin and into the diseased blood vessel.When the balloon inflates, it presses the occluding material against the lumen walls to force open the channel(See Figure 4.). After the procedure, the physician deflates and removes the balloon. Sometimes, the physician will place a hollow, thin mesh tube (stent) on the balloon and position it against the artery wall. It remains in place after the balloon catheter is removed and keeps the artery opened. A more invasive procedure involves rerouting blood around the occluded area using a vein graft that bypasses the obstruction (coronary artery bypass graft [CABG]). One end of the graft vessel is sutured to the aorta and the other end is sutured to the coronary artery below the blocked area. This graft reestablishes blood flow to the heart muscle(See Figure 5.).
High blood pressure, or hypertension (HTN), is a contributing factor in all of the conditions described above. In simple terms, hypertension is defined as a systolic pressure greater than 140 mm Hg or a diastolic pressure greater than 90 mm Hg. Hypertension causes the left ventricle to enlarge (hypertrophy) as a result of increased work. Some cases of HTN are secondary to other disorders, such as kidney malfunction or endocrine disturbance, but most of the time the causes are unknown, a condition described as primary or essential hypertension. Changes in diet and life habits are the first line of defense in controlling HTN. Drugs that are used include diuretics to eliminate fluids, vasodilators to relax the blood vessels, and drugs that prevent the formation or action of angiotensin, a substance in the blood that normally acts to increase blood pressure.