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9 Cards in this Set
- Front
- Back
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Gross Anatomy of the Heart |
I. The Pericardium: 1. The heart is enclosed in a double-walled sac called the pericardium. 2. The parietal pericardium consists of a tough fibrous layer of dense connective tissue with a thin,smooth, moist serous layer. 3. The serous layer turns in at the base of the heart, forming the visceral pericardium covering the heart surface. 4. Between the parietal and visceral pericardia is a space called the pericardial cavity. It contains pericardial fluid that lubricates the membrane and allows the heart to beat almost without friction. |
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II. The Heart Wall |
· The heart of consists of three layers: 1. The epicardium (visceral pericardium) is a serous membrane overlying a thin layer of areolar tissue. In many areas, it has thick deposits of adipose tissue. 2. The myocardium is composed of cardiac muscle and forms the bulk of the heart. It performs the work of the heart. 3. The endocardium is made up of a layer of endothelium overlying a thin layer of areolar tissue. It forms the smooth inner lining of the chambers and valves and is continuous with the endothelium of the blood vessels. |
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III. The Chambers |
1. The heart has four chambers. 2. The right and left atria recieve blood flowing to the heart. 3. The two inferior chambers, the left and right ventricles, pump the blood into the arteries for distribution elsewhere. 4. Other features of the heart include the atrioventricular sulcus, the anterior and posterior interventricular sulci, and the interventricular septum. |
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IV. The Valves |
1. Valves prevent the backflow of blood into the heart. 2. The pulmonary semilunar valve guards the opening from the right ventricle to the pulmonary trunk. 3. The aortic semilunar valve guards the opening from the left ventricle to the aorta. 4. An atrioventricular (AV) valve guards the opening between each atrium and ventricle. The right AV valve is also known as the tricuspid valve; the left is also called the bicuspid or mitral valve. String-like chordae tendineae attach the valve cusps to papillary muscles. 5. The opening and closing of the heart valves is the result of pressure gradients from one side of the valve cusps to the other. |
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V. The Coronary Circulation |
1. The first branches off the aorta are the left and right coronary arteries. 2. The left coronary artery supplies blood to the left side of the heart and divides into the anterior interventricular and circumflex arteries. 3. The right coronary artery supplies blood to the right side of the heart and divides into the marginal and posterior interventricular arteries. 4. A myocardial infarction (heart attack) occurs when any of the coronary arteries become occluded and a portion of the heart muscle dies from lack of blood flow. 5. Venous drainage refers to the route by which blood leaves an organ; blood leaving capillaries collects in small veins (venules) that nerve to form larger veins. 6. The great cardiac vein drains the anterior aspect of the heart, the middle cardiac vein that collects blood from the posterior aspect of the heart, and the small cardiac vein drains the right side of the heart. 7. All cardiac veins drain into the coronary sinus which empties into the atrium. 8. In most of the body, arterial blood flow is greater when the ventricles are contracting than when they relax. In the coronary arteries, however, flow is greater when the ventricles relax. |
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General Anatomy of Blood Vessels |
A. Circulatory Routes 1. The usual route of blood flow around the body is heart to arteries to arterioles to capillaries to venules, then veins, and back to the heart. 2. An artery is any vessel that carries blood away from the heart. A vein is any vessel that carries blood toward the heart. 3. Usually, blood flows through only one capillary bed before returning to the heart. An exception is a portal system in which blood flows through two separate capillary beds on it's return to the heart. Portal systems are found between the hypothalamus and anterior pituitary, in the kidneys, and between the intestines and liver. 4. Anastomoses are places where two or more vessels merge without including a capillary (e.g. vein to vein, artery to artery, or artery to vein). |
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B. The Vessel Wall |
· The walls of arteries and veins are made up of three layers called tunics: 1. The tunica external (tunica adventitia) is the outermost layer, made up of loose connective tissue. It anchors the vessels in place and provides passage for the vasa vasorum that supply blood to the vessel wall. 2. The tunics media, or middle layer, is the thickest layer of the vessel, made up mostly of smooth muscle. It is responsible for vasoconstriction and vasodilation. 3. The tunica interna (tunica intima) consists of endothelium overlying a basement membrane and a sparse layer of fibroconnective tissue. It provides a smooth surrounding through which blood passes. |
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Anatomy of the Pulmonary Circuit |
A. The pulmonary circuit begins with the pulmonary trunk that branches into the right and left pulmonary arteries, each of which leads to a lung. B. In the lung, pulmonary arteries branch into lobar arteries that carry blood to each lobe of a lung. These arteries further subdivide and lead to capillary beds that surround each alveolus. C. After leaving the alveolar capillaries, pulmonary blood, now carrying oxygen, flows into venules and veins, ultimately leading to the two pulmonary veins that leave the lungs and drain into the left atrium. |
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Hepatic Portal System |
·The hepatic portal vein is formed from the union of the superior mesenteric and gastrospienic vein. ·The superior mesenteric vein drains the entire small intestine and the proximal portions of the large intestine. · The gastrosplenic vein is formed from the union of the inferior mesenteric and splenic vein. ·The splenic vein drains the spleen and pancreas, and the inferior mesenteric vein drains the distal portion of the large intestine. ·Before entering the liver, the hepatic portal is joined by the right and left gastric veins, which drain the lesser curvature of the stomach. |
