Describe and explain how three features of the cells in the proximal convoluted tubule allow the rapid reabsorption of amino acids into the blood.

Aquaporins are water-channel proteins inserted into the cell-surface membranes of cells in the nephron in response to ADH. Name the two parts of the nephron where ADH causes these aquaporins to be inserted.

Aquaporins only allow water molecules to pass through. Suggest and explain why.

An increase in the solute concentration (osmolarity) of blood plasma stimulates the release of ADH. Give the location of the receptors that detect this increase and explain how the release of ADH will affect the solute concentration of the blood plasma.