Ion channels are a diverse group of pore-forming proteins that provide selective pathways for the movement of ions (Na+, K+,Ca2+, C1-,etc) across the lipid membrane barrier.Aquaporins facilitate water movement across cell membranes in response to osmotic gradients.There is an increasing body of information on the molecular structure and functional roles of ion and water channels in health and disease, linking channel function at the molecular level to organ physiology.