The kidney is a complex organ with distinct layers, each performing specific functions essential for filtering blood and producing urine. The kidney has three main layers: 1. Renal Cortex: This is the outermost layer of the kidney. It contains the glomeruli (where blood filtration begins) and the proximal convoluted tubules and distal convoluted tubules* (parts of the nephron responsible for reabsorption and secretion). Function: Primary site for filtration of blood and the initial stages of urine formation. It also plays a role in reabsorption* of water, electrolytes, and nutrients. 2. Renal Medulla: This is the middle layer, located beneath the cortex. It is composed of cone-shaped structures called renal pyramids*. The pyramids contain the loops of Henle and collecting ducts*. Function: Crucial for regulating the concentration of urine*. The loops of Henle create a salt gradient that allows the collecting ducts to reabsorb water, concentrating the urine and conserving body water. 3. Renal Pelvis: This is the innermost layer, a funnel-shaped structure that collects urine from the nephrons. It is continuous with the ureter*, the tube that carries urine from the kidney to the bladder. Function: Acts as a collection basin* for urine before it is transported out of the kidney.