The material produced by the endocrine gland is carried through the blood, while the material produced by the outer secretion gland is carried through the tubes to various organs for various functions. For example, sweat glands secrete sweat to cool the skin, and sebum glands provide oil to make the skin smooth.Also, a tear fountain makes tears and moistensSome exocrine glands secrete substances that moisturize and smooth the surfaces of organs in the body. The outer glands in the mouth or stomach produce digestive juices that help digest food.Some exocrine glands secrete a substance called pulmonary hormones.Lung hormones are secreted by many kinds of animals and play an important role in communicating with each other.Some of the outer secretions are made up of only one cell.Most exocrine glands release secretions in response to stimulation of the local nerve endings. But there is also an exocrine gland that is controlled by hormones.For example, gastric glands are stimulated by gastrin, a hormone secreted by the stomach, which releases digestive juices. External glands can also be affected by various diseases and cause problems in the secretion.I often think of the thymus in my chest as a fountain.The thymus serves to protect the body from illness.The lymph nodes in the neck, armpit, etc. are also thought to be springs, but these structures do not produce any secretions.Lymphatic nodules, like thymus, serve to protect the body from disease.