Chapter 18: The Cardiovascular System: The Heart
Homework Questions/Objectives (1-18)
1. Describe the size, shape, location, and orientation of the heart in the thorax. • 250 to 350 grams about the size of a fist, within the mediastinum and tilts toward the left side of the body√
2. Name the coverings of the heart.
• Pericardium – doubled-walled sac that encloses the heart. • Fibrous Pericardium – superficial part of pericardium, protects, anchors and prevents the heart from overfilling • Serous Pericardium – deep to the fibrous pericardium, a thin, slippery, two-layer serous membrane that forms a closed sac around the heart. • Parietal Layer – lines the internal surface off the fibrous pericardium and attaches to the large arteries exiting the heart. • Epicardium – Visceral layer of the Serous Pericardium that lines the external heart surface
3. Describe the structure and function of each of the three layers of the heart wall. • Endocardium – inside layer of the heart wall, sheet of endothelium, lines the heart chambers and covers the fibrous skeleton of the valves
• Myocadium – middle layer of heart wall, composed mainly of cardiac muscle, the layer that pumps
• Epicardium – Viseral layer of the Serous Pericardium that lines the external heart surface
4. Describe the structure and functions of the four heart chambers. Name each chamber and provide the name and general route of its associated great vessel(s). • Left Atria – left superior chamber of the heart that receives oxygenated blood from the lungs
• Right Atria – right superior chamber of the heart the receives oxygen-poor blood from the body
• Left Ventricle – left inferior chamber of the heart that pumps oxygenated blood to the body
• Right Ventricle – left inferior chamber of the heart that pumps oxygen-poor blood to the lungs
5. Trace the pathway of blood through the heart.
• Ensure unidirectional blood flow through the heart
• Semilunar Valve – valve between the left ventricle and the aorta
• Pulmonary Semilunar Valve - valve between the right ventricle and the pulmonary trunk
• Tricuspid Valve – the right (AV) atrioventricular valve, has three flexible cusps (flaps of endocardium reinforced by connective tissue cores)
• Mitral Valve – the left (AV) atrioventricular valve, has two flexible cusps (flaps of endocardium reinforced by connective tissue) resembles the two-sided bishop’s miter
6. Name the major branches and describe the distribution of the coronary arteries. • •Pulmonary circuit
• Right atrium
• tricuspid valve
• right ventricle
• pulmonary semilunar valve
• pulmonary trunk
• pulmonary arteries
• pulmonary veins
• left atrium
• •Systemic circuit
7. Name the heart valves and describe their location, function, and mechanism of operation. • •Left Coronary Artery – runs toward the left side of the heart and then divides into two major branches • Anterior Interventricular Artery – follows the anterior interventricular sulcus and supplies blood to the interventricular septum. • Circumflex Artery – supplies the left ventricle and the posterior walls of the left ventricle.
• •Right Coronary Artery – courses to the right side of the heart, where it also gives rise to two branches • Right Marginal Artery – serves the myocardium of the lateral side of the heart • oPosterior interventricular Artery – runs to...
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