Chapter 24: Pathophysiology of Hypertension
A 52-year-old man presents to your office for prevention of cardiovascular disease. His examination is notable for a blood pressure (BP) of 153/98 mm Hg. He wants to know about factors that would predispose him to hypertension. Which of the following is not associated with hypertension?
B. Excess potassium intake
The answer is B. (Hurst’s The Heart, 14th Edition, Chap. 24) Although primary hypertension is heterogeneous, some of the main causes of high BP are known. For example, overweight and obesity may account for 65% to 75% of the risk for primary hypertension (option C). Sedentary lifestyle, excess intake of alcohol or salt, and low potassium intake are also known to increase BP in some patients (options A, B, D, and E).1
A 23-year-old man is involved in a car accident and is bleeding into his abdomen. Which of the following systems do not regulate blood pressure (BP) acutely?
A. Arterial baroreceptors
C. Central nervous system (CNS)
D. Renin-angiotensin-aldosterone system (RAAS)
E. Increase in vasodilation
The answer is E. (Hurst’s The Heart, 14th Edition, Chap. 24) With rapid blood loss, three important neural control systems begin to function powerfully within seconds: (1) the arterial baroreceptors, which detect changes in BP and send appropriate autonomic reflex signals back to the heart and blood vessels to return the BP toward normal (option A); (2) the chemoreceptors, which detect changes in oxygen or carbon dioxide in the blood and initiate autonomic feedback responses that influence BP (option B); and (3) the central nervous system (CNS) (option C), which responds within a few seconds to ischemia of the vasomotor centers in the medulla, especially when BP falls below about 50 mm Hg. Within a few minutes or hours after a BP disturbance, additional controls react, including (1) a shift of fluid from the interstitial spaces into the blood in response to decreased BP (or a shift of fluid out of the blood into the interstitial spaces in response to increased BP); (2) the RAAS, which is activated when BP falls too low and suppressed when BP increases above normal (option D); and (3) multiple vasodilator systems that are suppressed when BP decreases and stimulated when BP increases above normal (option E).
Which of the following alters ...