Final answer:
Diastolic pressure is the minimal pressure against the blood vessel walls during the relaxation phase of the heartbeat, known as diastole. It is normally less than 80 mm Hg and serves as an indication of the resting pressure level in the arteries.
Step-by-step explanation:
Diastolic pressure, which is the lower of the two numbers recorded when measuring arterial blood pressure, represents the pressure against the blood vessel walls when the heart is relaxed. Specifically, it is the minimal value corresponding to the pressure that remains during ventricular relaxation, or diastole. This pressure is crucial as it indicates the baseline level of pressure in arteries in the times between heartbeats.
Blood pressure consists of systolic and diastolic measurements. Systolic pressure is the higher value and indicates the pressure when the ventricles contract and pump blood out of the heart. Diastolic pressure is the lower value during the cardiac cycle, occurring when the ventricles are filled with blood and the heart is in a state of relaxation, or diastole. Normal diastolic pressure is generally defined as less than 80 mm Hg.