heart quiz

A&P Test 2 The Heart HW Questions Study online at https://quizlet.com/_86uma4 The Cardiac Cycle The cardiac cycle reflects a series of electrical and mechanical events; these changes can be observed on a series of graphs. The electrocardiogram (ECG) tracing reflects atrial and ventricular depolarization and repolarization. The P wave corresponds to atri- al depolarization, the QRS complex to ventricular depolarization (and also atrial repolarization), and the T wave reflects ventricular repolarization. Pressure changes in the left ventricle, aorta, and left atria are correlated to changes in volume as blood moves through the four chambers of the heart; there is passive blood flow and the my- ocardial layer of the heart is responsible for contraction, or systole, and relaxation, or diastole. Two sets of valves—atrioventricular and semilunar—regulate blood flow and keep blood moving in a one-way direction. As these valves open and close, observe the changes in the pressure and volume graphs as well as the heart sounds that are produced. ECG Electrocardiogram True or False: The role of the chordae tendineae is to open the AV valves at the appropriate time. False Chordae tendineae anchor the cusps of the AV valves to the pap- illary muscles protruding from the ventricular walls. The chordae tendineae and the papillary muscles act as tethers that anchor the valve cusps in their closed position. If the cusps were not anchored, they would be blown upward (everted) into the atria, in the same way an umbrella is blown inside out by a gusty wind. The papillary muscles contract with the other ventricular musculature so that they take up the slack on the chordae tendineae as the full force of ventricular contraction hurls the blood against the AV valve cusps. The greater the mass of tissue in an organ, the greater its need for an adequate blood supply. Which chamber of the heart has the highest probability of being the site of a myocardial infarction? Left Ventricle The left ventricle actively pumps blood to almost all of the body's tissues via the aorta. It has to generate much greater force during contraction than any other heart chamber. The heart is actually how many pumps? Two pumps. Yes, the right side of the heart pumps to/from the lungs (pulmonary circuit) and the left side of the heart pumps to/from the rest of the body (the systemic circuit). Which chamber receives blood from the superior and inferior vena cavae? Right Atrium Yes, the right atrium receives unoxygenated blood from the sys- temic circuit. Which heart chamber receives blood from the pulmonary veins? Left Atrium Yes, the left atrium receives oxygenated blood from the pulmonary veins. Which heart chamber pumps unoxygenated blood out the pul- monary trunk? Right Ventricle Yes, the right ventricle pumps unoxygenated blood out the pul- monary trunk to the lungs. Which chamber pumps oxygenated blood out the aorta to the systemic circuit? Left Ventricle Yes, the left ventricle pumps oxygenated blood out the aorta to the entire body (systemic circuit). Besides cardiac muscle, what muscle tissue type is involuntary and displays autorhythmicity (also called "automaticity")? Smooth Muscle Select the correct statement about the function of myocardial cells. The entire heart contracts as a unit or it does not contract at all. Compared to skeletal muscle, cardiac muscle ________. has gap junctions that allow it to act as a functional syncytium The atrioventricular (AV) valves are closed ________. when the ventricles are in systole quiescent period period of total heart relaxation During each cardiac cycle there is a period of time in which both 2 / 3