Final answer:
The bottom number in a blood pressure reading, the diastolic pressure, represents the cessation of the Korotkoff sounds which occur when the blood flows freely through the artery without turbulence. The systolic pressure is the higher number indicating arterial pressure during heartbeats.
Step-by-step explanation:
When measuring blood pressure, two values are provided: the systolic pressure and the diastolic pressure. The systolic pressure, which is the higher number, signifies the pressure in the arteries during heartbeats. The diastolic pressure is the lower number, indicating arterial pressure when the heart is at rest between beats. Korotkoff sounds are the noises heard with a stethoscope during blood pressure measurement. The first Korotkoff sound occurs when the cuff's pressure is equal to the systolic pressure, indicating blood beginning to spurt into the artery. The cessation of Korotkoff sounds occurs when the cuff's pressure equals the diastolic pressure, signifying that blood flows freely through the artery without turbulence.
The bottom number in a blood pressure reading stands for the diastolic pressure, which indicates the cessation of the Korotkoff sounds, not the change in sounds. A typical normal blood pressure reading is expressed as 120/80 mm Hg, where 120 represents the systolic pressure and 80 represents the diastolic pressure.