Which component is NOT part of the digestive system?

The pituitary gland is not part of the digestive system because it is an endocrine gland responsible for producing and secreting hormones that regulate various bodily functions, including growth, metabolism, and reproduction. The digestive system, on the other hand, includes organs specifically involved in the mechanical and chemical breakdown of food, as well as the absorption of nutrients.

The stomach, oesophagus, and liver are all integral components of the digestive system. The stomach aids in the breakdown of food through mechanical churning and gastric juices, the oesophagus transports food from the mouth to the stomach, and the liver plays a crucial role in producing bile, which is necessary for the digestion and absorption of fats. Thus, identifying the pituitary gland as the outlier highlights a clear distinction between endocrine and digestive functions.