Munuainen

Munuainen is the Finnish word for the kidney, the paired excretory organs found in vertebrates. In Finnish anatomy and medicine the plural form is munuaiset. Kidneys are located retroperitoneally on either side of the spine in the lumbar region and are essential for maintaining internal homeostasis.

Structurally, a kidney contains an outer cortex and an inner medulla composed of many functional units called nephrons. Nephrons perform blood filtration, tubular reabsorption and secretion, and produce urine. Through these processes kidneys regulate fluid and electrolyte balance, remove metabolic wastes and toxins, and contribute to acid–base balance. They also have endocrine roles, producing hormones such as renin (which helps control blood pressure), erythropoietin (which stimulates red blood cell production), and contributing to activation of vitamin D.

Disorders affecting the kidneys include acute kidney injury, chronic kidney disease, glomerulonephritis and nephrolithiasis (kidney stones). Clinical management ranges from medical therapy to renal replacement treatments such as dialysis and transplantation in advanced failure.

The term Munuainen is also encountered as a Finnish surname. In Finnish-language sources and contexts, munuainen is the standard term used in education, clinical practice and public health to refer to the organ and its related functions and diseases.