sentences:  It is opposed by osmotic pressure (30 mmHg, 4.0 kPa) and hydrostatic pressure (20 mmHg, 2.7 kPa) of solutes present in capsular space.This difference in pressure is called effective pressure (25 mmHg, 3.3 kPa).In hemodialysis centers, ultrafiltration takes place in a hemofilter on the hemodialysis machines, when the blood pressure is greater than the dializate pressure (difference = transmembrane pressure (TMP)).