What is the primary function of the spleen in the human body?

The primary function of the spleen in the human body is to filter blood and recycle iron. The spleen plays a critical role in the immune system by filtering out old or damaged red blood cells and pathogens from the blood. In doing so, it identifies and removes cellular debris, which helps to maintain healthy blood circulation.

Additionally, the spleen is involved in the recycling of iron from hemoglobin when red blood cells are broken down. This iron can then be used to produce new red blood cells, thereby contributing to the body’s overall hematopoietic activity. This process also ensures that resources are efficiently utilized in maintaining the proper levels of iron in the body, which is essential for oxygen transport and overall metabolic function.

The other options do not accurately represent the spleen's primary functions. The production of hormones is mainly associated with glands such as the thyroid or adrenal glands, storing glucose is primarily a function of the liver and muscle tissues, and body temperature regulation is largely managed by the hypothalamus and skin, not the spleen.