- Proximal tubule:
NaCl and water, along with some ions and nutrients are reabsorbed.
- Descending limb of loop of Henle:
Reabsorption of water continues by osmosis.
- Ascending limb of loop of Henle:
Reabsorption of NaCl continues.
- Distal tubule:
Secretion of H+ helps regulate pH.
- Collecting duct:
More NaCl is reabsorbed to maintain a
high
osmolarity in the inner medulla.
Excretion occurs when urine is expelled from the urinary bladder through the
urethra.
Review: 
