26 notecards = 7 pages (4 cards per page)
When the semilunar valves are open, which of the following are occurring?
A)2, 3, 5, 6
The portion of the intrinsic conduction system located in the superior interventricular septum is the
An ECG provides information about
B)Movement of the excitation wave across the heart
The sequence of contraction of the heart chamber is
C)Both atria followed by both ventricles
The fact that the left ventricle wall is thicker than the right reveals that
B)Pumps blood against greater resistance
The chordae tendinease
B)Prevents the AV valve flaps from everting
In the heart, which of the following apply?
C)1, 2, 3,
The activity of the heart depends on intrinsic properties of cardiac muscle and on neural factors. Thus,
D)all of the above.
Freshly oxygenated blood is first received by the
Atrial depolarization, initiated by the SA node, causes the P wave.
Describe the location and position of the heart in the body.
The heart is enclosed within the mediastinum. It lies anterior to the vertebral column and posterior to the sternum. It tips slightly to the left.
Describe the pericardium and distinguish between the fibrous and the serous pericardia relative to histological structure and function
The pericardium has two layers, a fibrous and a serous layer. The outer fibrous layer is a fibrous connective tissue that protects the heart and anchors it to surrounding structures. The inner serous layer (squamous epithelial cells) lines the fibrous layer as the parietal serous pericardium and at the base of the heart continues over the heart surface as the visceral serous pericardium. The visceral serous pericardium is the outermost layer of the heart wall, that is, the epicardium.
Trace one drop of blood from the time it enters the right atrium until it enters the left atrium. What is the circuit called?
(a)Describe how the heart contraction and relaxation influences coronary blood flow
a. When the ventricles begin to relax following contraction, blood flows back toward the ventricles, getting caught in the semilunar valves. During this time, the coronary arteries are actively delivering blood to the myocardium. During ventricular contraction, the coronary vessels are compressed and ineffective in blood delivery. (pp. 667, 670)
The refractory period of cardiac muscle is much longer than that of skeletal muscle. Why is a desirable functional property?
A longer refractory period of cardiac muscle is desirable because it prevents the heart from going into prolonged or tetanic contractions, which would stop its pumping action. (p. 673)
(a)What are the elements of the intrinsic conduction system in order beginning with pacemaker?
a. The elements of the intrinsic conduction system of the heart, beginning with the pacemaker, are: the SA node or pacemaker, AV node, AV bundle, right and left bundle branches, and the subendocardial conducting network. (pp. 675–676)
Draw a normal ECG pattern. Label and explain the significance of its waves.
The P wave results from impulse conduction from the SA node through the atria during atrial depolarization. The QRS complex results from ventricular depolarization and precedes ventricular contraction. Its shape reveals the different size of the two ventricles and the time required for each to depolarize. The T wave is caused by ventricular repolarization. (pp. 677–678)
Define cardiac cycle, and follow the events of one cycle.
The cardiac cycle includes all events associated with the flow of blood through the heart during one complete heartbeat. One cycle includes a period of ventricular filling (mid-to-late diastole at the end of which atrial systole occurs), isovolumetric contraction (early ventricular systole), ventricular ejection (mid to late ventricular systole), and isovolumetric relaxation (early ventricular diastole). (pp. 679–680)
What is cardiac output, and how is it calculated?
Cardiac output is the amount of blood pumped out by the left ventricle in one minute. It can be calculated by the following equation: cardiac output = heart rate × stroke volume. (p. 681)
Discuss how Frank-Starling law of the heart helps to explain the influence of venous return on stroke volume
The Frank-Starling law explains that the critical factor controlling stroke volume is the degree of stretch of the cardiac muscle cells just before they contract. The important factor in the stretching of cardiac muscle is the amount of blood returning to the heart and distension of the ventricles. (p. 682)
Describe the common function of the foramen ovale and the ductus arteriosus in a fetus.
a. In a fetus, the common function of the foramen ovale and the ductus arteriosus is to allow blood to bypass the pulmonary circulation, and move directly into the systemic circulation.
Cardiac tamponade is the compression of the heart that occurs when blood or fluid builds up in the space between the myocardium (the muscle of the heart) and the pericardium (the outer covering sac of the heart) (p. 661)
a. To auscultate the aortic valve, place the stethoscope over the second intercostal space at the right sternal margin. To auscultate the mitral valve, place the stethoscope over the heart apex, in the fifth intercostal space in line with the middle of the clavicle. (p. 679)
Failure of the left ventricle (which pumps blood to the body) can result in chest pain due to dying or dead ischemic cardiac cells; pale, cold skin due to lack of circulation of blood from blocked ventricular contraction; and moist sounds in the lower lungs due to high pressure and pooling of blood in the pulmonary circulation because of nonfunction of the left ventricle. (pp. 668–669)
Oxygen-deficient blood returning from the systemic circulation to the right heart will pass repeatedly around the systemic circuit, while oxygenated blood returned from the lungs is continually recycled through the pulmonary circuit. (pp. 686–687)
Gabriel, being a user of an injectable drug, probably was infected by a bacteria-contaminated (“dirty”) needle used to administer heroin. (p. 690)