Blood Pressure and Hypertension
Blood pressure is the amount of tension in the veins and arteries as the heart pumps. Normal blood pressure is between 110/70 and 120/80. The higher number is the systolic reading, or the pressure in the vessels when the heart contracts. The lower number is the diastolic reading, or the pressure in the vessels when the heart relaxes. With high blood pressure, or hypertension, the pressure in the vessels is greater than 140/90. There are factors that cause hypertension and two common factors are blood vessel diameter and fluid volume.
About ACE Inhibitors
ACE inhibitors are a class of drugs prescribed for the treatment of high blood pressure. There are several ACE inhibitors on the market and doctors often prescribe them because they have fewer side effects than other blood pressure medications. ACE inhibitors are also prescribed for other conditions, like migraines and scleroderma. ACE stands for angiotensin-converting enzyme, an enzyme that converts angiotensin I into angiotensin II.
About Angiotensin II
Angiotensin II is a hormone that constricts the blood vessels. Angiotensin II also stimulates the adrenal glands to release aldosterone, which causes the kidneys to retain sodium and fluid. Another function of angiotensin is to stimulates the release of vasopressin, a hormone that causes the kidneys to retain fluid.
How Angiotensin II Affects Blood Pressure
Under normal circumstances, angiotensin II helps maintain balance in the body. Blood vessels need to constrict to stop bleeding--or reduce blood flow to certain areas of the body during the fight-or-flight response. People need aldosterone and vasopressin to maintain the fluid balance in their bodies. When the system breaks, however, the same hormone can cause hypertension. Constricted blood vessels increase blood pressure, the same way crimping a water hose increases the force of the water through the hose. Excess fluid levels also raise blood pressure by increasing the volume of fluid through the constricted vessel--much like turning up the faucet on a crimped hose.
How ACE Inhibitors Lower Blood Pressure
ACE inhibitors lower blood pressure by reducing the amount of angiotensin II in the blood. The blood vessels expand, allowing for easier blood flow and the kidneys reduce blood fluid volumes by releasing more water into the urine, and out of the body.
