The kidney filters 250 mmol of calcium ions a day in pro-urine ( or glomerular filtrate ), and resorbs 245 mmol, leading to a net average loss in the urine of about 5 mmol / d.
12.
Epithelial cell proliferation and fluid secretion that lead to cystogenesis are two hallmark features in ADPKD . During the early stages of cystogenesis, cysts are attached to their parental renal tubules and a derivative of the glomerular filtrate enters the cysts.
13.
In congestive heart failure ( a cause of pre-renal azotemia ) or any other condition that causes poor perfusion of kidneys, the sluggish flow of glomerular filtrate results in excessive absorption of BUN and elevation of its value in blood.
14.
As a result, the filtrate leaving the Bowman's capsule is very similar to blood plasma ( filtrate or glomerular filtrate is composed of blood plasma minus plasma protein i . e . it contains all the components of blood plasma except the proteins ) in composition as it passes into the proximal convoluted tubule.
15.
It is then excreted by the kidneys which simply pass most of the urea in the glomerular filtrate on into the urine without active resorption or excretion by the renal tubules ( a relatively small proportion of the urea in the tubules diffuses passively back into the blood as its concentration in the tubules rises when water, without urea, is removed from the tubular fluid ).
16.
Kidneys play a very large role in human osmoregulation by regulating the amount of water reabsorbed from glomerular filtrate in kidney tubules, which is controlled by hormones such as antidiuretic hormone ( ADH ), aldosterone, and angiotensin II . For example, a decrease in water potential of detected by osmoreceptors in hypothalamus, which stimulates ADH release from pituitary gland to increase the permeability of the wall of the collecting ducts in the kidneys.
