Approximately how many nephrons are there within each kidney?

Each human kidney contains approximately 1 million nephrons. Nephrons are the functional units of the kidney, responsible for filtering blood, removing waste, and regulating water and electrolyte balance. The number of nephrons is crucial for maintaining efficient kidney function, and having around 1 million in each kidney allows for the necessary filtration processes to occur effectively.

This number can vary slightly among individuals but is generally accepted as being around 1 million per kidney. Therefore, selecting 1 million as the answer reflects a widely recognized estimate in anatomy and physiology. Understanding the role and quantity of nephrons is essential for grasping how kidneys manage homeostasis in the body, including fluid balance and waste elimination. The variations in the other options, like 500,000 or 2 million, are not typically representative of the nephron population in healthy adult kidneys.