1. The correct answer is b. During the preceding diastolic period, the blood in the aorta and pulmonary artery has run off, so the pressure in these vessels drops. As the ventricles begin to contract at the beginning of systole, the pressure in the ventricles increases in the aorta and pulmonary artery, thus forcing the aortic and pulmonic valves open. Blood moves forward during systole into the aorta and pulmonary artery; therefore these two valves must be open.

2. The correct answer is c. Hypovolemia leads to a decrease in preload that then leads to a decrease in cardiac output. The falling output causes a fall in pressure that is sensed by osmoreceptors in the aortic arch and carotid bifurcation, which then causes activation of the cardioaccelerator center in the brainstem. The increased sympathetic outflow stimulates an increase in heart rate and contractility, thus increasing the cardiac output (CO = R × SV). The sympathetic nervous system is the earliest compensatory mechanism to be activated.

3. The correct answer is b. The lipoprotein that has been identified in atherosclerotic plaque is LDL, the cholesterol-carrying lipoprotein. HDL is the lipoprotein that clears cholesterol from the blood.

4. The correct answer is c. The bulging of the arterial plaque into the lumen of the blood vessel creates turbulent blood flow, which results in bruits and thrills on physical examination. It may also cause a diminished pulse, and the blood pressure may rise because of the loss of distensibility of the artery.

5. The correct answer is d. Because of autonomic neuropathy, diabetics often have silent ischemia. Women also tend to not have classic angina symptoms but rather shoulder or abdominal discomfort rather then the typical substernal chest pain.

6. The correct answer is c. When infarcted myocardial cells die, they release intracellular substances into the blood that serve as a cardiac marker of MI. The stress response to an MI results in elevation of blood sugar and an elevation of the S-T segment, indicating infarction or transmural ischemia.

7. The correct answer is c. With hypertension, some cerebral edema develops at night when the individual is lying down. When the individual is upright during the day, venous drainage from the head decreases the edema and the headache improves. Severe headache with visual disturbances may occur with more severe levels of blood pressure.

8. The correct answer is c. Hypertension damages blood vessels, especially at bifurcations, thus initiating atherosclerotic plaque development. The turbulent blood flow created by the irregularity of the arterial walls causes bruits in the renal, aorta, and iliac arteries. None of the other choices indicates end-organ damage.

9. The correct answer is d. An increase in preload improves myocardial contractility and cardiac output to a point because an increase in venous return/blood volume in the ventricle causes increased tension in the myocardial fibers. If the preload is excessive, however, the actin and myosin if the myocardial fibers are spread too far apart and the strength of contraction is diminished.