Abstract:Dorland's Illustrated Medical Dictionary defines the heart as "the viscus of cardiac muscle that maintains the circulation of the blood". It is divided into four cavities; two atria and two ventricles. The left atrium receives oxygenated blood from the lungs. From there the blood passes to the left ventricle, which forces it via the aorta, through the arteries to supply the tissues of the body. The right atrium receives the blood after it has passed through the tissues and has given up much of its oxygen.
The blood then passes through the right ventricle into the lungs where it gets oxygenated. There are four major valves in the heart; the left atrioventricular valve (also known as the mitral or bicuspid valve), the right atrioventricular valve (tricuspid), aortic valve, and the pulmonary valve. The heart tissue itself is nourished by the blood in the coronary arteries.2Position of the Heart Within the Body:The heart is placed obliquely in the chest. The two atria are directed upwards and backwards to the right and are at the level of the fifth through the eight dorsal vertebrae.
The apex of the heart points downwards and forwards to the left and corresponds to the interspace between the fifth and sixth ribs, two inches below the left nipple. Its atrial border corresponds to a line drawn across the sternum on a level with the upper border of the third costal cartilage. Its lower border (apex) corresponds to a line drawn across the lower end of the same bone, near the xiphoid process. Its upper surface is rounded and convex, directed upwards and forwards, and formed mainly by the right ventricle and part of the left ventricle. The posterior surface of the heart is flattened and rests upon the diaphragm muscle.
Of its two borders, the right is the longest and thinnest, the left is shorter but thicker and round.Size:In an adult, the heart measures about five inches in length, three and a half inches in the broadest part of its transverse diameter, and two and a half inches in its antero-posterior. The average weight in the male varies from ten to twelve ounces. In the female, the average weight is eight to ten ounces. The heart will continue to grow in size up to an advanced period of life. This growth is more obvious in men than in women.3Circulation of Blood in an Adult:The heart is subdivided by a longitudinal muscular septum into two lateral halves which are named right and left according to their position.
In this figure, SN = sinus node; AVN = AV node; RA = right atrium; LA
The normal Mitral Valve controls blood flow between the upper (left atrium) and lower chamber (left ventricle) of the left side of the heart. The mitral valve allows blood to flow from the left atrium into the left ventricle, but not flow the other way. With each heartbeat, the atria contract and push blood into the ventricles. The flaps of the mitral and tricuspid valves open to let blood through. Then, the ventricles contract to pump the blood out of the heart. The flaps of the mitral and tricuspid valves close and form a tight seal that prevents blood from flowing back into the atria (nhlbi.nih.gov).
In the “Tell-Tale Heart” by Edgar Allan Poe, the narrator is extremely uncanny due to the reader’s inability to trust him. Right from the beggining the reader can tell that the narrator is crazy although the narrator does proclaim that he is sane. Since a person cannot trust a crazy person, the narrator himself is unreliable and therefore uncanny. Also as the story progress the narrator falls deeper and deeper into lunacy making him more and more unreliable, until the end of the story where the narrator gives in to his insanity, and the reader loses all ability to believe him.
of the heart: one chamber is on the top and one chamber is on the
Furthermore, Aristotle and Galen’s theories contributed to the Renaissance revival of heart anatomy. This reawakening made it possible for physicians to indicate the basic arrangement of the heart. It became commonly accepted that the heart was divided into four parts: two ventricles (lower chambers that pump blood out) and two auricles (upper chamber that r...
The behavior of the narrator in The Tell-Tale heart demonstrate characteristic that are associated with people with obsessive-compulsive disorder and paranoid schizophrenia . When Poe wrote this story in 1843 obsessive-compulsive disorder and paranoia had not been discovered. However in modern times the characteristics demonstrated by the narrator leads people to believe that he has a mental illness. Poe’s narrator demonstrates classic signs throughout the story leading the reader to believe that this character is mad
Our heart is encircled by blood vessels. These blood vessels are called coronary arteries. They originate in the aorta and supply the heart muscle with oxygen rich blood. Coronary arteries consist of Right Coronary Artery, that branches into Marginal RCA and Posterior Descending Artery, and Left Main Coronary Artery, which branches into Left Circumflex, Marginal LCA and Left Anterior Descending Artery.
The Tell-Tale Heart: An Analysis In Edgar Allan Poe’s short-story, “The Tell-Tale Heart,” the storyteller tries to convince the reader that he is not mad. At the very beginning of the story, he asks, "...why will you say I am mad? " When the storyteller tells his story, it's obvious why. He attempts to tell his story in a calm manner, but occasionally jumps into a frenzied rant.
Elaborate: The cardiac cycle of the heart is divided into diastole and systole stages. Diastole refers to the period of relaxation experienced by the atria and ventricles. Systole is the contraction of the atria and ventricles. The pattern of blood flow starts in the left atrium to right atrium then into the left ventricle and right ventricle. During its course, blood flows through the mitral and tricuspid valves. Simultaneously, the right atrium is granted blood from the veins through the superior and inferior vena cava. The job of the superior vena cava is to transport de-oxygenated blood to
The heart serves as a powerful function in the human body through two main jobs. It pumps oxygen-rich blood throughout the body and “blood vessels called coronary arteries that carry oxygenated blood straight into the heart muscle” (Katzenstein and Pinã, 2). There are four chambers and valves inside the heart that “help regulate the flow of blood as it travels through the heart’s chambers and out to the lungs and body” (Katzenstein Pinã, 2). Within the heart there is the upper chamber known as the atrium (atria) and the lower chamber known as the ventricles. “The atrium receive blood from the lu...
Just as breast cancer is killing our African American women, heart disease is also one of the major diseases killing our women. Heart disease is one of the nation’s leading causes of death in both woman and men. About 600,000 people die of heart disease in the United States (Americas heart disease burden, 2013). Some facts about heart disease are every year about 935,000 Americans have a heart attack. Of these, 610,000 are a first heart attack victim. 325,000 happen in people who have already had a heart attack. Also coronary heart disease alone costs the United States $108.9 billion each year. This total includes the cost of health care services, medications, and loss of productivity. Deaths of heart disease in the United States back in 2008 killed about 24.5% of African Americans.
The heart is two sided and has four chambers and is mostly made up of muscle. The heart’s muscles are different from other muscles in the body because the heart’s muscles cannot become tired, so the muscle is always expanding and contacting. The heart usually beats between 60 and 100 beats per minute. In the right side of the heart, there is low pressure and its job is to send red blood cells. Blood enters the right heart through a chamber which is called right atrium. The right atrium is another word for entry room. Since the atrium is located above the right ventricle, a mixture of gravity and a squeeze pushes tricuspid valve into the right ventricle. The tricuspid is made up of three things that allow blood to travel from top to bottom in the heart but closes to prevent the blood from backing up in the right atrium.
It is about the size of a person's fist. The heart has four chambers. The upper two chambers are the right artium and left atrium, and the lower two are the right ventricle and left ventricle. Blood is pumped through the chambers, aided by four heart valves. The valves open and close to let the blood flow in only one direction.
Scientific interest in the heart goes back centuries. Some of the most basic understandings about the operation and specifically the electrical currents of the heart were discussed during the May 17, 1888 Proceedings of the Royal Society of London by Professor J.A. McWilliam of the University of Aberdeen. The following conclusions were based on his studies of mammalian hearts in cats, dogs, rabbits, rats, hedgehogs, and guinea-pigs.