Hypertension & Coronary Artery Disease Q 25

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Which of the following parameters is the major determinant of diastolic blood pressure?

  

     A. Baroreceptors

     B. Cardiac output

     C. Renal function

     D. Vascular resistance

    

    

Correct Answer: D. Vascular resistance

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Vascular resistance is the impedance of blood flow by the arterioles that most predominantly affects the diastolic pressure. Vascular resistance is used to maintain organ perfusion. In certain disease states, such as congestive heart failure, there is a hyper-adrenergic response, causing an increase in peripheral vascular resistance. Prolonged increases in blood pressure affect several organs throughout the body.

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Option A: Baroreceptors are a type of mechanoreceptor allowing for the relay of information derived from blood pressure within the autonomic nervous system. Information is then passed in rapid sequence to alter the total peripheral resistance and cardiac output maintaining blood pressure within a preset, normalized range.

Option B: Cardiac output determines systolic blood pressure. Cardiac output is the product of heart rate (HR) and stroke volume (SV) and is measured in liters per minute. HR is most commonly defined as the number of times the heart beats in one minute. SV is the volume of blood ejected during ventricular contraction or for each stroke of the heart. Not all of the blood that fills the heart by the end of diastole (end-diastolic volume or EDV) can be ejected from the heart during systole. Thus the volume left in the heart at the end of systole is the end-systolic volume (ESV).

Option C: Clinically, the most practical tests to assess renal function is to get an estimate of the glomerular filtration rate (GFR) and to check for proteinuria (albuminuria). Tests of renal function have utility in identifying the presence of renal disease, monitoring the response of kidneys to treatment, and determining the progression of renal disease.

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