Physiology IV (Cardiovascular)

During exercise, which of the following cardiovascular changes is primarily responsible for increasing cardiac output?

• Increased stroke volume
• Decreased heart rate
• Increased systemic vascular resistance
• Decreased preload

Which of the following is the most significant factor controlling coronary blood flow during diastole?

• Left ventricular contraction
• Aortic pressure
• Heart rate
• End-systolic volume

In a healthy individual, the rate of venous return is most directly influenced by which of the following?

• Cardiac output
• Central venous pressure
• Total peripheral resistance
• Left atrial pressure

The Frank-Starling mechanism primarily ensures which of the following?

• Increased preload decreases cardiac output
• Increased afterload enhances contractility
• Increased preload leads to increased stroke volume
• Increased heart rate compensates for decreased preload

Which of the following best describes the function of the SA node?

• Pacemaker of the heart
• Controls ventricular contraction
• Maintains atrial contraction
• Controls stroke volume

Which of the following ions is most responsible for the plateau phase of the cardiac action potential?

• Sodium
• Calcium
• Potassium
• Chloride

Which type of receptor primarily controls the vasoconstriction in arterioles?

• Beta-1 receptors
• Muscarinic receptors
• Alpha-1 receptors
• Beta-2 receptors

The major determinant of resistance in the cardiovascular system is which of the following?

• Blood pressure
• Blood viscosity
• Vessel diameter
• Stroke volume

The Valsalva maneuver typically causes an initial decrease in which of the following?

• Heart rate
• Venous return
• Systemic vascular resistance
• Cardiac output

Which of the following conditions is associated with a decrease in systemic vascular resistance?

• Septic shock
• Hemorrhage
• Hypertension
• Cardiogenic shock