Question

Explain how kidney help for maintain water balance

Answer 1

The kidneys maintain our body's water balance by controlling the water concentration of blood plasma. The kidneys also control salt levels and the excretion of urea. Water that is not put back into the blood is excreted in our urine.
As the blood passes through the kidneys, all the small molecules are filtered out of the blood.

This includes molecules of:

water
salt
glucose
urea (a waste product from the breakdown of proteins)
The kidneys then reabsorb all of the glucose and as much water and salt as the body needs, putting them back into the blood. This leaves some water and salt, and all of the urea, which is now called urine. The urine passes from the kidneys to the bladder, where it is stored prior to being excreted from the body.

The kidneys do more than just control the body’s water balance. They also control:

The level of salts in the blood.

The excretion of urea and other metabolic waste.
The kidneys maintain our water balance by producing urine of different concentrations.

When the water level of our blood plasma is low, more water is reabsorbed back into the blood and the urine becomes more concentrated.

When the water level of our blood plasma is high, less water is reabsorbed back into the blood and our urine is more dilute.

The level of water in the blood plasma can vary depending on:

External temperature - when it is hot, we sweat more and lose water, thereby making the blood plasma more concentrated.

Amount of exercise - if we exercise, we get hot and increase our sweating, so we lose more water and the blood plasma becomes more concentrated.

Fluid intake - the more we drink, the more we dilute the blood plasma. The kidneys respond by producing more dilute urine to get rid of the excess water.

Salt intake - salt makes the plasma more concentrated. This makes us thirsty, and we drink more water until the excess salt has been excreted by the kidneys.

HOPE IT HELPS

Answer 2

Kidney is a specialised organ which helps in purification of blood and absorbs the waste such as uria, excess water, salt, glucose etc... then this waste moves to the urinary bladder through ureters...the urine is stored there until there is a pressure to urge to release it..then it is excreted through urethra..

So.. kidney absorbs all the excess water from blood and excretes it..