HISTORY OF HEART RESEARCH, William Harvey Explains Blood Circulation

Circulatory System
HEART Anatomy Arrhythmias Cardiac Cycle Cardiac Output Congenital Heart Defect Control Of The Heart Rate Coronary Arteries Coronary Heart Disease Diseases Of The Heart Endocardium Function Of The Heart Generation Of The Heartbeat Heart Failure Heart Valves History Of Heart Research Myocardium Pericardium Heart Structure Heart Valve Malfunction Other Forms of Heart Disease

Blood INTRODUCTION ROLE OF BLOOD COMPOSITION OF BLOOD Plasma Red Blood Cells Blood Type White Blood Cells Platelets and Clotting PRODUCTION AND ELIMINATION OF BLOOD CELLS Red Blood Cell Diseases White Blood Cell Diseases Coagulation Diseases BLOOD BANKS Blood Transfusion Blood Count Blood donation and registry Blood gas analysis Blood sugar tests Blood typing and crossmatching Blood urea nitrogen test Blood-viscosity reducing drugs Blood Culture Blood Clot in the Legs Causes Blood Clot in the Legs Symptoms Blood Clot in the Legs
COMPONENTS OF THE CIRCULATORY SYSTEM OPERATION AND FUNCTION Systemic Circulation Pulmonary Circulation Additional Functions Blood Pressure
Digestive system Esophagus Gall bladder Large intestine Lips, cheeks and palate Salivary glands Serous membranes Small intestine Stomach Tunics
Teeth Tongue Digestive Process in Mouth Sleep Right Mouth Guard
Endocrine system Glandular Structure Gonads Hormones Pancreas Parathyroid Glands Pineal Gland Pituitary Gland Pituitary Hormones Thymus Thyroid Gland
Respiratory system


HISTORY OF HEART RESEARCH, William Harvey Explains Blood Circulation

 A groundbreaking work in the history of medicine, English physician William Harvey’s “Anatomical Essay on the Motion of the Heart and Blood in Animals” named the heart as the organ responsible for pumping blood. Although criticized when first published in 1628, Harvey��s work was soon accepted by scientists and laid the groundwork for modern physiology.

 Scientific knowledge of the heart dates back almost as far as the beginnings of recorded history. The Egyptian physician Imhotep made observations on the pulse during the 2600s bc. During the 300s bc the Greek physician Hippocrates studied and wrote about various signs and symptoms of heart disease, and the Greek philosopher Aristotle described the beating heart of a chick embryo. Among the first people to investigate and write about the anatomy of the heart was another Greek physician, Erasistratus, around 250 bc. Erasistratus described the appearance of the heart and the four valves inside it. Although he correctly deduced that the valves prevent blood from flowing backward in the heart, he did not understand that the heart was a pump. Galen, a Greek-born Roman physician, also wrote about the heart during the second century ad. He recognized that the heart was made of muscle, but he believed that the liver was responsible for the movement of blood through the body.

 Heart research did not greatly expand until the Renaissance in Europe (14th century to 16th century). During that era, scientists began to connect the heart’s structure with its function. During the early 16th century the Spanish physician and theologian Michael Servetus described how blood passes through the four chambers of the heart and picks up oxygen in the lungs. Perhaps the most significant contributions were made by English physician William Harvey, who discovered the circulation of blood in 1628. Harvey was the first to realize that the heart is a pump responsible for the movement of blood through the body. His work revealed how the heart works with the blood and blood vessels to nourish the body, establishing the concept of the circulatory system.

 The 20th century witnessed extraordinary advances in the diagnosis of heart diseases, corrective surgeries, and other forms of treatment for heart problems. Many doctors had become interested in measuring the pulse and abnormal heartbeats. This line of research culminated in the 1902 invention of the electrocardiograph by Dutch physiologist Willem Einthoven, who received the Nobel Prize for this work in 1924. Another major advance in diagnosis was cardiac catheterization, which was pioneered in 1929 by German physician Werner Forssmann. After performing experiments on animals, Forssmann inserted a catheter through a vein in his arm and into his own heart—a stunt for which he was fired from his job. Two American physicians, André Cournand and Dickinson Richards, later continued research on catheterization, and the technique became commonly used during the 1940s. The three scientists received the Nobel Prize in 1956 for their work.

 At the beginning of the 20th century, most doctors believed that surgery on the heart would always remain impossible, as the heart was thought to be an extremely delicate organ. Most of the first heart operations were done in life-or-death trauma situations. American physician L. L. Hill performed the first successful heart surgery in the United States in 1902, sewing up a stab wound in the left ventricle of an 8-year-old boy. The next year, French surgeon Marin Théodore Tuffier removed a bullet from a patient’s left atrium.

 Surgery to correct some congenital defects involving blood vessels also helped lay the foundations for surgery on the heart itself. In 1938 American surgeon Robert Gross performed the first successful surgery to treat an open ductus arteriosus, tying the vessel closed with thread. In 1944 Gross and Swedish surgeon Clarence Crafoord each performed successful surgery for coarctation of the aorta. The same year, American surgeon Alfred Blalock and surgical assistant Vivien Thomas performed the first successful operation to correct tetralogy of Fallot. But the greatest leap forward came in 1953, when American physician John Gibbon introduced the heart-lung machine, a device to oxygenate and pump blood during surgery on the heart. This invention made open-heart surgery—with the heart stopped for the duration of the operation—possible. It led to now-routine surgical techniques such as valve replacement, correction of congenital defects, and bypass surgery.

 The rapid pace of scientific discovery during the 20th century has also led to many nonsurgical treatments for diseases of the heart. The introduction of antibiotics to treat bacterial infections greatly reduced sickness and deaths due to heart disease from rheumatic fever, endocarditis, and other infections involving the heart, although these infections remain a significant threat in many developing nations. Many effective drugs to control hypertension, reduce cholesterol, relieve angina, limit damage from heart attacks, and treat other forms of heart disease have also been developed. Advances in electronics led to implantable pacemakers in 1959 and implantable defibrillators in 1982.

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