Answer:
(a) The arteries supplying the heart muscle are known as coronary arteries. These arteries can become diseased due to a condition called coronary artery disease (CAD). CAD is primarily caused by atherosclerosis, which is the buildup of plaque inside the arteries. Plaque consists of cholesterol, fatty deposits, calcium, and other substances that gradually accumulate on the inner walls of the arteries. Over time, this buildup narrows the coronary arteries and restricts blood flow to the heart muscle. The plaque can also rupture, leading to the formation of blood clots that can further block the arteries and cause a heart attack.
(b) During an operation on the diseased coronary arteries, a patient is put on a heart-lung machine, also known as a cardiopulmonary bypass machine. The heart-lung machine takes over the functions of the heart and lungs during the operation. It allows the surgeon to stop the patient's heart temporarily and redirect the blood flow away from the heart, enabling them to perform the necessary procedures on the coronary arteries.
Step-by-step explanation:
The heart-lung machine consists of a pump, an oxygenator, and a heat exchanger. The pump maintains blood circulation throughout the body, while the oxygenator adds oxygen to the blood and removes carbon dioxide, functioning as an artificial lung. The heat exchanger helps regulate the temperature of the blood as it circulates through the machine.
By diverting blood away from the heart, the heart-lung machine provides a bloodless and motionless surgical field, allowing the surgeon to perform intricate procedures on the coronary arteries without the interference of a beating heart. This ensures greater precision and safety during the operation. Once the surgical procedures are complete, the heart-lung machine is gradually weaned off, and the patient's heart resumes its normal function.