What is the outermost layer of the kidney called?

The outermost layer of the kidney is known as the cortex. The cortex plays a crucial role in the kidney's function, containing numerous nephrons, which are the functional filtration units that help in the formation of urine. The cortex is positioned just beneath the renal capsule, which provides protection to the kidney, and surrounds the inner medulla, where the collecting ducts and renal pyramids are located.

The cortex is involved in processes such as filtration and reabsorption, contributing significantly to the regulation of water, electrolytes, and waste products in the body. Understanding the structure of the kidney, including the distinction between the cortex and the medulla, is essential for comprehending how the kidney functions in maintaining homeostasis in the body. This anatomical knowledge is pivotal when exploring renal physiology and the mechanisms of kidney-related diseases.