(4) If the bladder is inflated, but the pressure within the bladder is less than
the lowest level of pressure within the artery (diastolic pressure), then the bladder
cannot collapse the artery. The pressure of the bladder may interfere somewhat with
the blood flow, but it cannot stop the blood flow (figure 5-5 D ). Thus, when the blood
continues to flow through the artery beneath the bladder without stopping, you know
that the pressure within the bladder is less than the lowest (diastolic) pressure of the
blood within the artery.
A Artery without the bladder--artery expands during heartbeat, returns to normal.
B Air pressure in the bladder is greater than the systolic
pressure--the artery stays collapsed.
C Air pressure in bladder is between systolic pressure and diastolic
pressure--artery collapsed except during heartbeat.
D Air pressure in bladder is less than diastolic pressure--artery does not
Figure 5-5. Effects of an inflated bladder on an artery.