How does inflating a blood pressure cuff affect brachial artery blood flow?
The correct answer and explanation is:
When a blood pressure cuff is inflated around the upper arm, it applies pressure to the brachial artery, which temporarily occludes or compresses it. This results in a blockage of blood flow through the artery. The cuff is inflated to a pressure higher than the systolic blood pressure, preventing blood from flowing through the artery for the duration of the inflation. During this period, blood flow to the arm is stopped, and no blood is able to pass beyond the cuff.
As the cuff inflates, it prevents arterial blood flow completely, causing the blood in the arteries below the cuff to be trapped. This pressure temporarily stops the movement of the blood through the brachial artery. When the cuff pressure is slowly released, the blood flow is restored, and blood begins to rush back into the arm. At this point, the medical professional listens to the sounds (Korotkoff sounds) produced by the turbulent blood flow through the partially compressed artery.
This process of occlusion and release is essential in measuring blood pressure. When the cuff pressure reaches the level where it is just below the systolic blood pressure, the blood starts to flow again and is heard through the stethoscope. The point where the first sound is heard corresponds to the systolic blood pressure. When the sounds disappear, the cuff pressure is at the diastolic blood pressure, indicating the point at which the artery is no longer constricted and blood flows freely.
Thus, inflating the cuff causes temporary cessation of blood flow, and as the pressure is gradually released, it allows for measurement of the systolic and diastolic pressures that represent the functional state of the brachial artery during the cardiac cycle.