Search results
Results from the WOW.Com Content Network
The vasa recta have a similar loop shape so that the gradient does not dissipate into the plasma. [citation needed] The mechanism of counter current multiplication works together with the vasa recta's counter current exchange to prevent the wash out of salts and maintain a high osmolarity at the inner medulla. [citation needed]
Whereas the peritubular capillaries surround the cortical parts of the tubules, the vasa recta go into the medulla and are closer to the loop of Henle, [1] [2] and leave to ascend to the cortex. [3] [4] Terminations of the vasa recta form the straight venules, branches from the plexuses at the apices of the medullary pyramids.
The loop of Henle is supplied by blood in a series of straight capillaries descending from the cortical efferent arterioles. These capillaries (called the vasa recta; recta is from the Latin for "straight") also have a countercurrent multiplier mechanism that prevents washout of solutes from the medulla, thereby maintaining the medullary ...
A comparison between the operations and effects of a cocurrent and a countercurrent flow exchange system is depicted by the upper and lower diagrams respectively. In both it is assumed (and indicated) that red has a higher value (e.g. of temperature) than blue and that the property being transported in the channels therefore flows from red to blue.
The blood exiting the efferent arterioles of these nephrons enter the vasa recta, which are straight capillary branches that deliver blood to the renal medulla. These vasa recta run adjacent to the descending and ascending loop of Henle and participate in the maintenance of the medullary countercurrent exchange system.
This allows for a countercurrent exchange system whereby the medulla becomes increasingly concentrated, but at the same time setting up an osmotic gradient for water to follow should the aquaporins of the collecting duct be opened by ADH.
The descending vasa recta, ascending vasa recta vessels, and the loop of Henle together form the countercurrent system of the kidney. In the afferent arteriole, blood is supplied at high pressure, which promotes filtration, and in the efferent arteriole, it is at low pressure, which promotes reabsorption .
The rete mirabile utilizes countercurrent blood flow within the net (blood flowing in opposite directions) to act as a countercurrent exchanger. It exchanges heat, ions, or gases between vessel walls so that the two bloodstreams within the rete maintain a gradient with respect to temperature, or concentration of gases or solutes.