The urinary system Anterior view of the female

The urinary system Anterior view of the female urinary organs. (a) Diagrammatic view. (b) X ray of urinary organs after injection of contrast medium (E. Marieb, HA&P, 2004).

A representative nephron The major functions of each segment of the nephron and collecting system (F. Martini, A&P, 2004)

The blood supply of the kidney (a) A sectional view, showing major arteries and veins. (b) Circulation in the renal cortex. (c) Flowchart of renal circulation. (d) Blood flow to the nephron (F. Martini, A&P, 2004).

Anatomy of nephrons and their vasculature (E. Marieb, HA&P, 2004)

Summary of nephron functions (E. Marieb, HA&P, 2004)

A Summary of renal function A general overview of steps and events (F. Martini, A&P, 2004)

The major fluid compartments of the body [Values are for a 70 -kg (154 -pound) male] (E. Marieb, HA&P, 2004)

Major sources of water intake and output (E. Marieb, HA&P, 2004)

Physiological mechanisms regulating the glomerular filtration rate (GFR) in the kidneys (E. Marieb, HA&P, 2004)

Mechanisms and consequences of aldosterone release (E. Marieb, HA&P, 2004)

Reabsorpion of filtered HCO 3 - is coupled to H+ secretion (E. Marieb, HA&P, 2004)

Generation of new HCO 3 - via buffering of excreted H+ by monohydrogen phosphate (HPO 42 -) (E. Marieb, HA&P, 2004) H+ from the dissociation of H 2 CO 3 is actively secreted by an H+- ATPase pump and combines with HPO 42 - in the lumen. HCO 3 generated at the same time leaves the basolateral membrane via an antiport carrier in a HCO 3 - - Cl- exchange process which maintains electroneutrality in the duct cells.

Generation of new HCO 3 - via glutamine metabolism and NH 4+ secretion (E. Marieb, HA&P, 2004) PCT cells metabolize glutamine to NH 4+ and HCO 3 -. NH 4+ (a weak acid) is then actively secreted by occupying the H+ site on the H+- Na+ co-transporter. The new HCO 3 - generated moves into the peritubular capillary blood.

Dialysis procedure. Hemodialysis (F. Martini, A&P, 2004) Preparation for hemodialysis typically involves the implantation of a pair of shunts connected by a loop that permits normal blood flow when the patient is not hooked up to the machine.