serve as the body’s filtration system, purifying and filtering bodily fluids, such as blood, as it circulates through
are located in the anterior region of the abdominal cavity, in front of the 12th ribs, behind the liver and stomach.
They are about 12 cm long, 6 cm wide, bean-shaped and of a dark reddish hue. The kidneys are surrounded by a mass of fatty
tissue which protects and insulates it, while keeping it in place along the abdominal wall.
receive their blood supply through the renal arteries. Blood is carried towards the outer edges of the organs, into the capillaries
where wastes are taken in by the nephrons, and then leaves the kidneys purified via the renal veins.
can be separated into three regions; the lighter colored renal cortex, the darker renal medulla, and finally, the innermost
region, the renal pelvis.
the specialized cells of the kidneys, are the filtration unit of the organ. Tubular in shape, the nephron is responsible for
the formation of urine after collecting waste from the blood.
the nephrons via the afferent capillaries, which branches into a structure called the glomerulus and wraps around the top
portion of the nephron, called the Bowman’s capsule. Here, solutes in the blood diffuse into the nephron, and are now
known as the glomerulus filtrate.
travels into the proximal tube of the nephron, where nutrients that are essential to the blood are reabsorbed into the peritubular
capillaries. The filtrate travels down the descending and ascending loops of the nephron, called the Loop of Henle, where
water and salt are reabsorbed into the capillaries.
solutes and wastes travel across the distal tube and down the nephron into the collecting duct which leads the ureters, and
ultimately the bladder, where the urine is expelled into the outside environment.
maintains homeostasis of internal fluids with the help of aldosterone and the antidiuretic hormone (ADH). ADH is sent to the
kidneys in response to changes in osmotic pressure and signals the kidney to either accelerate or stop reabsorbtion of water.
Aldosterone works with the kidneys to monitor and maintain the salt and water balance, and works in response to changes in
blood pressure. The kidneys maintain the pH balance of the blood by regulating the carbonic acid and bicarbonate buffer system
in the blood.