Question 1

A 60-year-old man has been told by his doctor that he has angina caused by myocardial ischemia. Which of the following treatments would be beneficial for him?&#10;A)Angiotensin converting enzyme inhibition&#10;B)Isometric exercise&#10;C)Chelation therapy such as EDTA&#10;D)Beta receptor stimulation&#10;E)Increased dietary calcium

Accepted Answer

Angiotensin converting enzyme inhibition is a recommended treatment for angina caused by myocardial ischemia. It helps by lowering blood pressure and decreasing the workload on the heart, ultimately reducing the risk of worsening angina, heart attack, or heart failure. Isometric exercise, chelation therapy such as EDTA, beta receptor stimulation, and increased dietary calcium are not proven to be effective treatments for angina caused by myocardial ischemia.

Question 2

Which of the following increases the risk of adverse cardiac events?&#10;A)Decreased blood levels of LDL&#10;B)Decreased blood levels of HDL&#10;C)Female gender&#10;D)Moderate hypotension&#10;E)Decreased blood triglycerides

Accepted Answer

Decreased blood levels of HDL (high-density lipoprotein, also known as "good cholesterol") are associated with an increased risk of adverse cardiac events, such as heart attack and stroke. The other options do not necessarily increase the risk of adverse cardiac events, and in some cases may even be protective (such as decreased blood levels of LDL and triglycerides). Female gender may be a risk factor for certain types of heart disease, but it is not a definitive predictor of adverse cardiac events. Moderate hypotension (low blood pressure) may actually be beneficial for cardiovascular health in some cases, although severe hypotension can be dangerous.

Question 3

The majority of venous blood flow leaves the heart muscle through which of the following?&#10;A)Anterior cardiac veins&#10;B)Azygos vein&#10;C)Bronchial veins&#10;D)Coronary sinus&#10;E)Thebesian veins

Accepted Answer

The majority of venous blood flow leaves the heart muscle through the coronary sinus, which is located on the surface of the heart and drains blood from the coronary veins. The other options mentioned are veins that drain other areas of the body or heart, but they do not carry the majority of venous blood flow from the heart muscle.

Question 4

Which is usually the most important controller of coronary blood flow?&#10;A)Adenosine&#10;B)Bradykinin&#10;C)Prostaglandins&#10;D)Carbon dioxide&#10;E)Potassium ions

Accepted Answer

Adenosine is the primary controller of coronary blood flow, especially during periods of increased metabolic demand. It is released when there is a lack of oxygen supply and helps to dilate the blood vessels in the heart, increasing blood flow to the area. While bradykinin, prostaglandins, carbon dioxide, and potassium ions may also play a role in coronary blood flow regulation, adenosine is the most important controller.

Question 5

Which of the following is normally associated with an increased tendency for the heart to fibrillate following a myocardial infarction?&#10;A)Current of injury from ischemic cardiac muscle&#10;B)Decreased extracellular potassium concentration&#10;C)Decreased sympathetic stimulation&#10;D)Increased extracellular sodium concentration&#10;E)Decreased cardiac volume

Accepted Answer

Current of injury results from the damaged or dying cardiac muscle cells, and it can disrupt the normal electrical conduction within the heart, leading to arrhythmias such as fibrillation.

Question 6

A 60-year-old man experienced an ischemia-induced myocardial infarction and died from ventricular fibrillation. What factor was most likely to increase the tendency of the heart to fibrillate after the infarction?

A)Low potassium concentration in the heart extracellular fluid
B)A decrease in ventricular diameter
C)Increased sympathetic stimulation of the heart
D)Low adenosine concentration
E)Decreased parasympathetic stimulation of the heart

Accepted Answer

Increased sympathetic stimulation of the heart can cause an increase in heart rate and contractility, leading to increased oxygen demand and potentially worsening ischemia. Additionally, sympathetic stimulation can increase the likelihood of ventricular fibrillation, as it increases the automaticity and excitability of cardiac cells, making them more prone to arrhythmias.

Question 7

A healthy 40-year-old man has been exercising maximally for 15 minutes. Which of the following conditions is likely to be present?&#10;A)Arteriolar resistance in the gastrointestinal bed is increased by 200%&#10;B)Cerebral blood flow is decreased to 50% of normal&#10;C)Heart rate is unchanged&#10;D)Cardiac output is increased 5%&#10;E)Right atrial pressure is increased to 10 mmHg

Accepted Answer

During maximal exercise, blood flow is redirected from the gastrointestinal tract to the muscles, increasing arteriolar resistance in the gastrointestinal bed.

Question 8

Which of the following normally causes vasodilation of skeletal muscle arterioles during exercise?&#10;A)Decreased plasma osmolality&#10;B)Decreased plasma nitric oxide concentration&#10;C)Increased plasma potassium concentration&#10;D)Decreased plasma adenosine concentration&#10;E)Increased plasma histamine concentration

Accepted Answer

During exercise, muscle cells generate action potentials that cause the release of potassium ions into the interstitial fluid, which then enters the blood plasma. An increase in blood potassium concentration causes the smooth muscle cells in the walls of arterioles to hyperpolarize, leading to vasodilation and increased blood flow to the active skeletal muscle.

Question 9

Which of the following vascular beds experiences the most vasoconstriction in a person near the end of a 5-mile run?&#10;A)Cerebral&#10;B)Coronary&#10;C)Exercising muscle&#10;D)Intestinal&#10;E)Skin

Accepted Answer

During intense exercise, such as near the end of a 5-mile run, the body prioritizes blood flow to areas that are crucial for the exercise, such as the muscles and the heart. The intestinal blood vessels experience the most vasoconstriction to divert blood to these areas, as digestion is not a priority during intense physical activity.

Question 10

At the onset of exercise, the mass sympathetic nervous system strongly discharges. Which of the following would you expect to occur?&#10;A)Increased sympathetic impulses to the heart&#10;B)Decreased coronary blood flow&#10;C)Decreased cerebral blood flow&#10;D)Reversed stress relaxation&#10;E)Dilation

Accepted Answer

At the onset of exercise, there is an increase in sympathetic impulses to the heart to increase cardiac output and meet the increased demand for oxygen by the working muscles. Increasing sympathetic impulses to the heart will cause an increase in heart rate and contractility. The other options are unlikely to occur at the onset of exercise.

Question 11

During mild exertion a 70-year-old man has an ischemia-induced myocardial infarction and dies from ventricular fibrillation. In this patient, which factor was most likely to increase the tendency of the heart to fibrillate after the infarction?

A)Increased parasympathetic stimulation of the heart
B)A decrease in ventricular diameter
C)Low potassium concentration in the heart extracellular fluid
D)A more negative ventricular membrane potential
E)Current of injury from the damaged area

Accepted Answer

The answer of During mild exertion a 70-year-old man has...

Question 12

Which of the following will elevate the plateau of the cardiac output curve?&#10;A)Surgically opening the thoracic cage&#10;B)Placing a patient on a mechanical ventilator&#10;C)Cardiac tamponade&#10;D)Increasing parasympathetic stimulation of the heart&#10;E)Increasing sympathetic stimulation of the heart

Accepted Answer

The answer of Which of the following will elevate the...

Deck 21: Muscle Blood Flow and Cardiac Output During Exercise; the Coronary Circulation and Ischemic Heart Disease