Reabsorption
Secretion
Substances that are useful to the body (such as glucose, water, and certain ions) undergo this process.
This process can take place in any section of the renal tubule.
Substances that undergo this process are excreted.
Substances that undergo this process are returned to the blood stream.
Metabolic wastes, toxins, drugs, and selected ions undergo this process.
This process can take place in the proximal tubule, distal tubule, and the collecting duct.