Professor Saltzman introduces the basic concepts of renal physiology. Professor Saltzman first introduces the function and anatomy of the kidney. Special attention is given to the cell types and structural aspect of the nephron, the functional unit of the kidney. Filtration, secretion of toxic waste, and reabsorption of water, ions, and nutrients through the glomerulus and various segments of the nephrons is discussed in detail. Finally, Professor Saltzman describes glomerular filtration rate as a function of pressure drop, which is regulated by afferent and efferent arterioles, to control how much volume being filtered through glomerulus.