Hypertension in African Americans
When there is any noted change in the blood pressure, the baroreceptors (situated in the carotid arteries and the arch of the aorta) send inhibitory impulses to the brainstem which has the sympathetic vasomotor center. The innervation of the cardiac and vascular smooth muscles by the efferent nerves in the systemic nervous system causes a decrease in heart rate, decrease in force of contraction, and dilation of peripheral arterioles. Under normal activities, the simultaneous increase in the parasympathetic nervous system activity results in a decrease in heart rate through the vagus nerve and reversely decrease blood pressure. But with consistent high blood pressure, the body does automatic reset occurs in the baroreceptors as a means to adapts to the “new normal” blood pressure levels. Overtime, the weakened response to the baroreceptors, as a result of aging from cardiovascular effects is a major factor of a lifetime hypertension risk. Moreover, the kidney’s regulation of the renin-angiotensin-aldosterone system also plays a vital role in controlling of blood pressure.
The juxtaglomerular apparatus produces the enzyme renin which changes angiotensinogen to angiotensin 1 inside the kidney. Then the angiotensin converting enzyme (ACE) converts angiotensin I to angiotensin II via the lungs exerting some effect on Blood pressure control. Angiotensin 2 is a potent vasoconstrictor