Blood pressure is the force of the blood exerted on the walls of the arterial blood vessels. Arterial blood pressure is highest during ventricular systole, and lowest during diastole. Normal blood pressure is 120 (systolic)/80 (diastole) mm Hg. Stretch-sensitive receptors known as baroreceptors are located in the walls of the aorta and carotid arteries branch out form the aorta. They monitor the pressure of blood flowing to the body and to the brain. An increase in blood pressure stretches the baroreceptors. Impulses are sent to the cardiovascular control centre in the medulla oblongata of the brain. From there, impulses are then sent via the parasympathetic nerve to the heart. This slows down the heartbeat, resulting in a decrease in blood pressure.
A decrease in blood pressure increases stimulation of the sino-atrial node by the sympathetic nerve. This increases the contraction of the cardiac muscles of the heart and the smooth muscles of the arteries. The blood pressure increases and returns to its normal level. A person’s blood pressure can be measured by using an instrument called a sphygmomanometer.
A decrease in blood pressure increases stimulation of the sino-atrial node by the sympathetic nerve. This increases the contraction of the cardiac muscles of the heart and the smooth muscles of the arteries. The blood pressure increases and returns to its normal level. A person’s blood pressure can be measured by using an instrument called a sphygmomanometer.
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