At the transition from the DCT to the collecting duct, about 20 percent of the original water is still present and about 10 percent of the sodium. If no other mechanism for water reabsorption existed, about 20–25 liters of urine would be produced. Now consider what is happening in the adjacent capillaries, the vasa recta.
If no other mechanism for water reabsorption existed, about 20–25 liters of urine would be produced. Now consider what is happening in the adjacent capillaries, the vasa recta.
In the presence of hormones, the kidney is able to concentrate the filtrate to be 20 times more concentrated than the glomerular plasma and PCT filtrate. The process of concentrating the filtrate occurs in the DCT and collecting ducts.
Explain the role of the loop of Henle, the vasa recta, and the countercurrent multiplication mechanisms in urine production Urine is the end product once the filtrate has been fully manipulated by the nephrons.
This process allows for the recovery of large amounts of water from the filtrate back into the blood, which produces a more concentrated urine. If less ADH is secreted, fewer aquaporin channels are inserted and less water is recovered , resulting in dilute urine.
The process of concentrating the filtrate occurs in the DCT and collecting ducts.
If aquaporin water channels are present, water will be osmotically pulled from the collecting duct into the surrounding interstitial space and into the peritubular capillaries.
The renal medulla has a concentration gradient with a low osmolarity superficially and a high osmolarity at its deepest point. The kidneys have expended a large amount of cellular energy to create this gradient, but what do the nephrons do with this gradient? In the presence of hormones, the kidney is able to concentrate the filtrate to be 20 times more concentrated than the glomerular plasma and PCT filtrate.
Explain the role of the loop of Henle, the vasa recta, and the countercurrent multiplication mechanisms in urine production. Urine is the end product once the filtrate has been fully manipulated by the nephrons. Until the filtrate passes through the renal papilla into the minor calyx, it can be affected by nephron processes.
By varying the amount of water that is recovered, the collecting ducts play a major role in maintaining the body’s normal osmolarity. If the blood becomes hyperosmotic, the collecting ducts recover more water to dilute the blood; if the blood becomes hyposmotic, the collecting ducts recover less of the water, leading to concentration of the blood.
In general, blood flows slowly in capillaries to allow time for exchange of nutrients and wastes. In the vasa recta particularly, this rate of flow is important for two additional reasons.