Question

Regulation of electrolytes and fluid volume by kidney

Answer 1

For making our body cells to function properly they will be surrounded in extracellular fluid that is relatively constant with regard to osmolality.  

Kidneys connection with neural and endocrine input controls volume and osmolality of extracellular fluid by changing amount of sodium and water extracted.  

Its accomplished primarily through alterations in sodium and water re-absorption and mechanisms of which changes inside each nephron segment.