The human kidney has many functions, all of which are important for sustaining life. The kidney controls blood osmolarity by filtering, reabsorbing, and secreting various ions found throughout the body. The kidney controls fluid volume in the body by this same mechanism. Additionally, the kidney produces erythropoietin and renin which stimulate the production of red blood cells and convert angiotensinogen to angiotensin I, respectively.

A very large loss of from the patient will lead to a drastic decrease in pH. Therefore, all alkalosis disorders can be ruled out. Additionally, because the pH decrease is unrelated to an increase in carbon dioxide, it is not a respiratory issue - leaving only metabolic acidosis as a diagnosis. Cystic fibrosis involves the overproduction of thick mucous, which causes severe respiratory pathology; other systems are affected too, but excess bicarbonate secretion is not associated with this genetic disease.

Obstruction bilaterally in the ureters leads to decreased GFR due to increased pressure retrograde from the ureters. Bowman space pressure increases to override the GFR pressure. Bowman space pressure does not favor filtration versus GFR pressure (favors filtration).

Serum osmolality is best estimated at around

The urine made within the kidney drains out from the renal pelvis and down the ureter to ultimately be stored in the bladder.

The renal capsule is the outermost structure of the kidney. It is the fibrous connective tissue kidney structure that directly surrounds the renal cortex, and is surrounded by a layer of adipose tissue that protects the kidney from trauma. The renal pyramids, renal sinus, and renal medulla are located deep within the kidney.