A compact collection of secretory cells that discharges its secretions through tubes or ducts opening on to a body surface or the gut. Exocrine glands are widely distributed in the skin of most terrestrial animals. Frogs, for example, possess a skin gland which forms a mucous secretion to prevent the skin drying out. Some also have poison glands, the secretions of which discourage attacks by predators. Glands within the nostrils and eyes keep delicate surface membranes moist and free from obstruction.
Sebaceous glands associated with hair follicles protect the skin of mammals.
The sweat glands aid heat loss in mammals. Exocrine glands of the digestive system provide saliva for the mouth, gastric juice for the stomach, pancreatic juice, and bile for the intestines. Mucous glands deliver a sticky coating for the lining membranes of the gut to protect them from the actions of the digestive juices, and to assist the smooth passage of food. Oxford University Press 2. A Dictionary of Science, Oxford University Press 4.