<span>The adrenal gland produces a hormone called aldosterone. Without this hormone, Na+ cannot be reabsorbed from the urine, and K+ cannot be secreted into it. K+ will build up in the blood, and Na+ will be lost in the urine.</span>
The answer is ultrafiltration. This is helped by the hydrostatic pressure and blood pressure in afferent renal arteriole. Molecules such as water, glucose, urea, sodium chloride, amino acids pass through the semipermeable membrane of the dense capillary network of the glomerulus to form glomerular filtrate. Some of these molecules are later reabsorbed in the renal tubules.
Strong, naive, perfect balance of strong and naive.
Alexander Fleming is the answer ;D