Final answer:
The arterial blood pressure in a relaxed state is represented by systolic and diastolic pressures. A normal blood pressure reading is generally considered to be less than 120/80 mm Hg, where the first number refers to systolic and the second to diastolic pressure.
Step-by-step explanation:
The arterial blood pressure of a certain individual in a state of relaxation is given by two numbers, representing the systolic and diastolic pressures. The systolic pressure is the higher number, typically around 120 mm Hg, which indicates the pressure in the arteries when the heart's ventricles contract and blood is ejected during systole. The diastolic pressure is the lower number, usually about 80 mm Hg, which represents the minimum arterial pressure during ventricular relaxation, or diastole. Normal blood pressure is defined as a systolic pressure less than 120 mm Hg and a diastolic pressure less than 80 mm Hg.
Blood pressure measurement reflects the force that blood exerts on the walls of arteries and is regulated through various mechanisms including the elasticity of the artery walls, vasoconstriction, vasodilation, and peripheral resistance. Understanding these numbers is crucial for assessing cardiovascular health.