Which of the following is considered an excretory gland?

The gall bladder is considered an excretory gland because it plays a crucial role in the excretion of bile, which is produced by the liver. Bile is essential for the digestion and absorption of fats in the small intestine, and it also helps in the elimination of waste products, such as bilirubin, from the body. The gall bladder stores and concentrates bile until it is needed for digestion, effectively functioning in the excretion of substances that are no longer needed by the body.

In contrast, while the pancreas produces hormones and enzymes vital for digestion, it is also known for its exocrine function but is primarily classified as an endocrine gland due to its hormonal secretions. The liver, while it produces bile and plays a significant role in metabolic processes, is not categorized as an excretory gland in this context because it processes and synthesizes rather than primarily excreting. The spleen, meanwhile, is involved in filtering blood and is important for immune functions, but it is not associated with excretion in the same way as the gall bladder.