大学英语circulatory system.pptVIP

Circulatory system Blood circulates throughout the body in the cardiovascular system, which consists of the heart and the blood vessels This system forms a continuous circuit that delivers oxygen and nutrients to all cells and carries away waste products. Also functioning in circulation is the lymphatic system, which drains fluid and proteins from the tissues and returns them to the bloodstream. The heart The heart is located between the lungs. The thick muscle layer of the heart wall is the myocardium. This is lined on the inside with a thin endocardium and is covered on the outside with a thin epicardium. The heart is contained within a fibrous sac, the pericardium. Each of the upper receiving chambers of the heart is an atrium (plural, atria). Each of the lower pumping chambers is a ventricle (plural, ventricles). The chambers of the heart are divided by walls, each of which is called a septum. Cardi/o: heart cardiocyte cardiology cardiomalacia cardiomelanosis bradycardia tachycardia coron/o: coronary coronary artery: the blood vessels that supply blood to the heart muscle Coronary heart disease (CHD) is a condition in which proper circulation of blood and oxygen are not provided to the heart and surrounding tissue. This result is due to a narrowing of the small blood vessels, which normally supply the heart with blood and oxygen. The typical cause of coronary heart disease is a condition known as atherosclerosis, which takes place with plaque and fatty build up on the artery walls, narrowing the vessels. Some more frequent symptoms of coronary heart disease include: Angina (chest pain)Heart attackShortness of breath coronavirus: Coronaviruses primarily infect the upper respiratory and gastrointestinal tract of mammals and birds. Four to five different currently known strains of coronaviruses infect humans. The most publicized human The Vascular System The vascular system consists of: 1. Arteries that car