Describe and explain how three structural features of the epithelial cells lining the proximal convoluted tubule (PCT) adapt them for the rapid reabsorption of glucose from the glomerular filtrate.
Identify the two regions of the renal tubule where ADH stimulates the insertion of aquaporins into the luminal membranes of the epithelial cells.
Aquaporins are highly selective channel proteins that allow the passage of water but prevent the passage of hydronium ions (H3O+\text{H}_3\text{O}^+H3O+). Suggest and explain how the structure of an aquaporin ensures this selectivity.
A decrease in the solute concentration (osmolarity) of blood plasma (such as after drinking a large volume of water) causes a reduction in ADH secretion. State the precise location of the receptors that detect this change, and explain how the resulting reduction in ADH release restores the solute concentration of the blood plasma to its normal range.
