Tubular reabsorption occurs along the renal tubules of the kidneys, explains Dr. Perry Carter of Midlands Technical College. A renal tubule consists of a proximal convoluted tubule, the loop of Henle and distal convoluted tubule. Filtrate from the renal corpuscle drains into the proximal convoluted tubule, where reabsorption immediately begins.
The different segments of the renal tubule have varying reabsorption capabilities, explains Dr. Carter.
The proximal convoluted tubule is the most active section for reabsorption, returning glucose, amino acids, vitamins, water, urea and various electrolytes back to the bloodstream. The descending portion of the loop of Henle continues water reabsorption, while the ascending portion continues electrolyte reabsorption.
The distal convoluted tubule is active in reabsorbing sodium, chlorine and calcium ions. The passing filtrate empties from the renal tubules into the collecting ducts, where additional electrolytes, water and urea are also reabsorbed.