Figure 6-3. A "typical" nephron.
d. The Collecting Tubule. The distal convoluted tubules of several nephrons
empty into a collecting tubule. The urine is then passed from the collecting tubule at the
papilla of the medullary pyramid. Several collecting tubules are present in each
e. Renal Pelvis. The renal pelvis is a hollow sac within the sinus of the kidney.
Urine from the pyramids collects into the funnel-shaped renal pelvis. The ureter then
drains the urine from the renal pelvis.
6-6. HORMONES INVOLVED IN THE FORMATION OF URINE
There are two main hormones involved in the formation of urine. These
hormones are the antidiuretic hormone (ADH), and aldosterone.
a. Antidiuretic Hormone. The antidiuretic hormone is a hormone secreted by
the pituitary gland. It acts on the distal and collecting tubules to increase water
reabsorption. Since more water is reabsorbed, the urine becomes more concentrated.