The Heart - 1 PDF

The Heart Gross Anatomy Intended Describe the gross structure of the heart to Learning include base, apex, named chambers, named valves, vessels entering and leaving the heart Outcome  Internal Structure of the heart The right side pumps deoxygenated blood to the lungs and the left...

The Heart Gross Anatomy Intended Describe the gross structure of the heart to Learning include base, apex, named chambers, named valves, vessels entering and leaving the heart Outcome  Internal Structure of the heart The right side pumps deoxygenated blood to the lungs and the left side pumps oxygenated blood to the whole body. Loading… Veins carry blood into the heart (vena cava and pulmonary vein) and arteries carry blood away from it (pulmonary artery and aorta) Overall shape and size of the heart Position of the Heart Loading… Overall shape, position and size of heart Roughly the same size (but not the same shape) as your closed fist. The heart rests on the diaphragm, near the midline of the thoracic cavity. The heart lies in the mediastinum an anatomical region that extends from the sternum to the vertebral column, from the first rib to the diaphragm, and between the lungs About two-thirds of the mass of the heart lies to the left of the body’s midline Shaped like an inverted cone  Base and Apex of the heart Base and apex of heart The base of the heart is opposite the apex and is its posterior aspect. It is formed by the atria (upper chambers) of the heart, mostly the left atrium The pointed apex is formed by the tip of the left ventricle (a lower chamber of the heart) and rests on the diaphragm. It is directed anteriorly, inferiorly, and to the left.  Four chambers of the heart  Myocardial thickness and function  Inferior transverse section Loading… through heart  Right Atrium Forms the right surface of the heart and receives blood from three veins: the superior vena cava, inferior vena cava, and coronary sinus (Veins always carry blood toward the heart.) Between the right atrium and left atrium is a thin partition called the interatrial septum (inter- = between; septum = a dividing wall or partition). Blood passes from the right atrium into the right ventricle through a valve that is called the tricuspid valve (because it consists of three cusps ). It is also called the right atrioventricular valve  Right Ventricle The cusps of the tricuspid valve are connected to tendonlike cords, the chordae tendineae which in turn are connected to papillary muscles. Internally, the right ventricle is separated from the left ventricle by a partition called the interventricular septum. Blood passes from the right ventricle through the pulmonary valve (pulmonary semilunar valve) into a large artery called the pulmonary trunk, which divides into right and left pulmonary arteries and carries blood to the lungs. Arteries always take blood away from the heart (a mnemonic to help you: artery = away).  Left Atrium The left atrium is about the same thickness as the right atrium and forms most of the base of the heart It receives blood from the lungs through four pulmonary veins. Blood passes from the left atrium into the left ventricle through the bicuspid (mitral) valve which, as its name implies, has two cusps. It is also called the left atrioventricular valve.  Left Ventricle The left ventricle is the thickest chamber of the heart and forms the apex of the heart Has chordae tendineae that anchor the cusps of the bicuspid valve to papillary muscles. Blood passes from the left ventricle through the aortic valve (aortic semilunar valve) into the ascending aorta Some of the blood in the aorta flows into the coronary arteries, which branch from the ascending aorta and carry blood to the heart wall. Remainder of the blood passes into the arch of the aorta and descending aorta (thoracic aorta and abdominal aorta). Branches of the arch of the aorta and descending aorta carry blood throughout the body. Myocardial Thickness and Function The thickness of the myocardium of the four chambers varies according to each chamber’s function. The thin-walled atria deliver blood under less pressure into the adjacent ventricles. Because the ventricles pump blood under higher pressure over greater distances, their walls are thicker Although the right and left ventricles act as two separate pumps that simultaneously eject equal volumes of blood, the right side has a much smaller workload. It pumps blood a short distance to the lungs at lower pressure, and the resistance to blood flow is small. The left ventricle pumps blood great distances to all other parts of the body at higher pressure, and the resistance to blood flow is larger. Therefore, the left ventricle works much harder than the right ventricle to maintain the same rate of blood flow. The anatomy of the two ventricles confirms this functional difference—the muscular wall of the left ventricle is considerably thicker than the wall of the right ventricle Detail needed…. Detail needed is the detail written down on the slides. Revision Flashcards are also available, which contain same level of detail.