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Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution which in this case is represented by body fluid) to keep the body fluids from becoming too diluted or concentrated.
Water is readily reabsorbed from the descending limb by osmosis. [ 3 ] Also, the medullary interstitium is highly concentrated (because of the activity of the ascending limb), leading to a strong osmotic gradient from the descending limb to the medulla.
Since water is also reabsorbed the volume of fluid in the loop of Henle is less than the PCT, approximately one-third of the original volume. The interstitium of the kidney increases in osmolarity outside as the loop of Henle descends from 600 mOsm/L in the outer medulla of the kidney to 1200 mOsm/L in the inner medulla.
The 'single effect' describes the fact that the ascending thick limb of the loop of Henle is not permeable to water but is permeable to sodium chloride. 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 ...
The descending limb of the loop of Henle is permeable to water but impermeable to solutes, due to the presence of aquaporin 1 in its tubular wall. Thus, water moves across the tubular wall into the medullary space, making the filtrate hypertonic (with a lower water potential). This is the filtrate that continues to the ascending limb. [2]
Variation in the rate of water excretion is an important survival function for mammals that have limited access to water. [135] The loop of Henle is the most prominent feature of the mammalian kidney. These loops provide the most efficient way to reabsorb water and create concentrated urine, allowing mammals to save water in their bodies. [138]
The recommended daily amount of drinking water for humans varies. [1] It depends on activity, age, health, and environment.In the United States, the Adequate Intake for total water, based on median intakes, is 4.0 litres (141 imp fl oz; 135 US fl oz) per day for males older than 18, and 3.0 litres (106 imp fl oz; 101 US fl oz) per day for females over 18; it assumes about 80% from drink and 20 ...
In hypertonic solutions water flows out of the cell and the cell shrinks (plasmolysis). In hypotonic solutions, water flows into the cell and the cell swells ( turgescence ). Osmotic shock or osmotic stress is physiologic dysfunction caused by a sudden change in the solute concentration around a cell , which causes a rapid change in the ...