Which organ is primarily responsible for producing insulin?

The pancreas is the organ primarily responsible for producing insulin, which is a critical hormone involved in regulating blood glucose levels. Insulin facilitates the uptake of glucose by cells, allowing them to use it for energy or store it for future use. The pancreas contains clusters of cells known as the islets of Langerhans, where insulin is produced and secreted in response to rising blood sugar levels, particularly after meals.

Other organs mentioned have different primary functions that do not include insulin production. For instance, the kidneys are primarily responsible for filtering blood and managing electrolyte levels, the liver plays a crucial role in metabolizing nutrients, detoxifying harmful substances, and storing glucose in the form of glycogen, while the stomach's main function lies in the digestion of food.