The Cardiovascular System: The Heart
Chapter 19
The Cardiovascular System: The Heart 1. How is the heart positioned in the mediastinum?
It rests on the diaphragm, near the midline of the thoracic cavity, with about two-thirds of the mass lying to the left of the body’s midline. 2. Which layer of the pericardium is both a part of the pericardium and a part of the heart wall?
Serous pericardium 3. What is the function of pericardial fluid?
Reduces friction between the membranes as the heart moves 4. From most superficial to deepest, what are the layers of the pericardium and heart wall?
Fibrous pericardium, serous pericardium, epicardium, myocardium, endocardium 5. What function do the auricles serve?
Slightly increases the capacity of the atria so that …show more content…
The anterior interventricular sulcus forms a boundary between which chambers of the heart?
Right and left ventricles 8. What structure separates the atria? The ventricles?
(a )interatrial septum; (b) interventricular septum 9. What is the main force that causes blood to flow through the heart and the heart valves to open and to close?
The blood flowing from areas of higher blood pressure to areas of lower blood pressure 10. As the ventricles contract, what prevents the atrioventricular valves from swinging upward into the atria?
Pressure of the ventricular blood driving the cusps upward until the valve are closed 11. Why does blood ejected into the pulmonary trunk or aorta normally not flow back through the semilunar valve?
Back-flowing blood in the ventricles force the semilunar valves to close 12. From which vessels do each of the atria receive blood? Into which vessels do the ventricles eject blood?
The right atrium receives blood from the vena cava and sends it to the right ventricles through the tricuspid valve; the right ventricle sends the blood into the pulmonary trunk through the pulmonary valve; the left atrium receives blood from the pulmonary veins and sends blood into the left ventricle through the bicuspid valve; the left ventricle sends blood from the left atrium into the aorta through the aortic …show more content…
Which component of the conduction system sets the pace of contraction in a normal heart?
Sinoatrial node 20. What is an electrocardiogram?
A recording of the electrical changes that accompany the heartbeat 21. How does each ECG wave relate to the phases of an action potential?
P wave: atrial depolarization; QRS complex which represents the onset of ventricular depolarization; T wave: ventricular replarization 22. What is the diagnostic significance of the ECG?
Useful in diagnosing abnormal cardiac rhythms and conduction patterns and in following the course of recovery from a heart attack 23. How does each ECG wage relate to contraction and relaxation of the atria and ventricles?
First wave: represents atrial depolarization which causes contraction of the atria; second wave: QRS complex which represents the onset of ventricular depolarization when ventricles contract; third wave: T wave which indicates ventricular repolarization and occurs just before the ventricles start to relax; relaxation of the atria is not usually evident in the ECG 24. Which term is uded for the contraction phase of the cardiac cycle? The relaxation phase? (a) Systole; (b)
The Cardiovascular System: The Heart 1. How is the heart positioned in the mediastinum?
It rests on the diaphragm, near the midline of the thoracic cavity, with about two-thirds of the mass lying to the left of the body’s midline. 2. Which layer of the pericardium is both a part of the pericardium and a part of the heart wall?
Serous pericardium 3. What is the function of pericardial fluid?
Reduces friction between the membranes as the heart moves 4. From most superficial to deepest, what are the layers of the pericardium and heart wall?
Fibrous pericardium, serous pericardium, epicardium, myocardium, endocardium 5. What function do the auricles serve?
Slightly increases the capacity of the atria so that …show more content…
The anterior interventricular sulcus forms a boundary between which chambers of the heart?
Right and left ventricles 8. What structure separates the atria? The ventricles?
(a )interatrial septum; (b) interventricular septum 9. What is the main force that causes blood to flow through the heart and the heart valves to open and to close?
The blood flowing from areas of higher blood pressure to areas of lower blood pressure 10. As the ventricles contract, what prevents the atrioventricular valves from swinging upward into the atria?
Pressure of the ventricular blood driving the cusps upward until the valve are closed 11. Why does blood ejected into the pulmonary trunk or aorta normally not flow back through the semilunar valve?
Back-flowing blood in the ventricles force the semilunar valves to close 12. From which vessels do each of the atria receive blood? Into which vessels do the ventricles eject blood?
The right atrium receives blood from the vena cava and sends it to the right ventricles through the tricuspid valve; the right ventricle sends the blood into the pulmonary trunk through the pulmonary valve; the left atrium receives blood from the pulmonary veins and sends blood into the left ventricle through the bicuspid valve; the left ventricle sends blood from the left atrium into the aorta through the aortic …show more content…
Which component of the conduction system sets the pace of contraction in a normal heart?
Sinoatrial node 20. What is an electrocardiogram?
A recording of the electrical changes that accompany the heartbeat 21. How does each ECG wave relate to the phases of an action potential?
P wave: atrial depolarization; QRS complex which represents the onset of ventricular depolarization; T wave: ventricular replarization 22. What is the diagnostic significance of the ECG?
Useful in diagnosing abnormal cardiac rhythms and conduction patterns and in following the course of recovery from a heart attack 23. How does each ECG wage relate to contraction and relaxation of the atria and ventricles?
First wave: represents atrial depolarization which causes contraction of the atria; second wave: QRS complex which represents the onset of ventricular depolarization when ventricles contract; third wave: T wave which indicates ventricular repolarization and occurs just before the ventricles start to relax; relaxation of the atria is not usually evident in the ECG 24. Which term is uded for the contraction phase of the cardiac cycle? The relaxation phase? (a) Systole; (b)