The patient may be asked to perform some exercise before the test in order to increase the heart rate, or they may be administered with medicine that increase the heart rate. A doppler echocardiogram is performed to examine the blood flow in the heart, by measuring the speed and direction of the blood flow. This test is usually performed as a part of the TTE and TEE test.
Reabsorbtion. Occuring more commonly within the nephron system than filtration, this is a form of active transport which takes the the useful substances for the body from the tubules and places them back into the blood filled capillaries.ithin the LOOP OF HENLE, the descending limb allows for the reabsorbtion of water through osmosis whereas the ascending limb allows for the passive and active transport of salts such as sodium to move out of the tubules and be reabsorbed.
Water reabsorption is a passive process: water is reabsorbed by osmosis. In most of the nephron, water reabsorption is unregulated and coupled to solute reabsorption.The ability to excrete urine that is more concentrated than the extracellular fluid (ECF) depends on the creation of a hyperosmotic environment in the medulla.As the collecting duct descends through the medulla, the increasing osmolarity in the interstitial fluid drives water reabsorption.he ability to excrete urine that is more concentrated than the extracellular fluid (ECF) depends on the creation of a hyperosmotic environment in the medulla. As the collecting duct descends through the medulla, the increasing osmolarity in the interstitial fluid drives water reabsorption.