Cortexes, also spelled cortices, refer to the outer layer of an organ, such as the brain, adrenal gland, or kidney. Synonyms for this term include cortex, cerebral cortex, cerebral mantle, and gray matter. The cerebral cortex is the most commonly referred to cortex and is responsible for perception, voluntary movement, thought processes, and consciousness. The adrenal cortex produces hormones vital for many bodily functions, including the fight or flight response. The renal cortex filters blood, removes waste, and reabsorbs nutrients. It's essential to understand the various cortexes and their functions for proper medical diagnosis and treatment.