1. Which of the following components is LEAST crucial to the continuous circulation of oxygenated blood throughout the body? A) Heart B) Spleen C) Vasculature D) Fluid volume - ANS-B The cardiac cycle begins with the onset of myocardial contraction and ends: A) as blood returns to the right atrium. B) as both ventricles are filling with blood. C) when the ventricles are emptied of blood. D) with the beginning of the next contraction. - ANS-D Afterload is defined as the: A) pressure in the aorta against which the left ventricle must pump. B) amount of resistance to blood flow offered by the heart valves. C) amount of blood ejected from the ventricle with each contraction. D) volume of blood remaining in the ventricles following contraction. - ANS-A Which of the following two factors DIRECTLY affect cardiac output? A) Preload and afterload B) Vessel size and stroke volume C) Stroke volume and pulse rate D) Blood pressure and pulse rate - ANS-C Which of the following statements regarding blood flow is correct? A) Ejection fraction is the percentage of blood that the heart pumps per contraction. B) If more blood returns to the heart, stroke volume decreases and cardiac output falls. C) As more blood is pumped with each contraction, the ejection fraction increases. D) The amount of blood that returns to the atrium remains fixed from minute to minute. - ANS-A Hemoglobin functions by: A) dissolving in blood plasma to create the partial pressure of carbon dioxide. B) binding to oxygen that is absorbed in the lungs and transporting it to the tissues. C) absorbing hydrogen ions in the blood in order to maintain acid-base balance. D) transporting red blood cells throughout the body to ensure adequate oxygenation. - ANS-B What aggregates in a clump and forms much of the foundation of a blood clot during the process of coagulation? A) Fibrin B) Calcium C) Plasmin D) Platelets - ANS-D Perfusion is defined as: A) the effective exchange of oxygen and carbon dioxide within the lungs and at the cellular level. B) the circulation of blood through an organ or tissue in amounts adequate to meet the body's demands. C) an ejection fraction that is adequate to maintain radial pulses or a systolic blood pressure of at least 90 mm Hg. D) the circulation of an adequate volume of blood to ensure uninterrupted cerebral and myocardial oxygenation. - ANS-B Which of the following organs or body systems requires a constant blood supply, regardless of external factors? A) Skin B) Muscles C) Kidneys D) Gastrointestinal tract - ANS-C Which of the following organs can sustain the longest period of inadequate perfusion? A) Gastrointestinal tract B) Kidneys C) Spinal cord D) Skeletal muscle - ANS-A An organ or tissue that is considerably colder than 98.6°F is better able to resist damage from hypoperfusion because: A) the body's metabolic rate is slower. B) cells shrink as body temperature falls. C) hypothermia promotes oxygen metabolism. D) hypothermia protects hemoglobin molecules. - ANS-A The amount of blood returned to the heart is called: A) preload. B) cardiac output. C) afterload. D) stroke volume - ANS-