Physiology, Arterial Pressure Regulation

Excerpt

In general, an individual’s “blood pressure,” or systemic arterial pressure, refers to the pressure measured within large arteries in the systemic circulation. This number splits into systolic blood pressure and diastolic blood pressure. Blood pressure is traditionally measured using auscultation with a mercury-tube sphygmomanometer. It is measured in millimeters of mercury and expressed in terms of systolic pressure over diastolic pressure. Systolic pressure refers to the maximum pressure within the large arteries when the heart muscle contracts to propel blood through the body. Diastolic pressure describes the lowest pressure within the large arteries during heart muscle relaxation between beating.

Arterial pressure directly corresponds to cardiac output, arterial elasticity, and peripheral vascular resistance. Blood pressure is remarkably easy to alter and can be affected by many activities. Maintaining blood pressure within normal limits is essential. A blood pressure between 140/80 mmHg to 159/99 mmHg is classified to as stage 1 hypertension. Categorization of Stage 2 hypertension is a pressure between 160/100 mmHg to 179/109 mmHg. Hypertensive urgency describes a blood pressure greater than 180/120 mmHg and hypertensive emergency refers to a very high blood pressure that results in potentially life-threatening symptoms and end-organ damage. Hypotension, on the other hand, is a blood pressure less than 90/60 mmHg. It is crucial for the body to be able to adjust to acute changes in blood pressure and for the patient to receive medical treatment or lifestyle adjustments for chronic variations.