Secretes

Secretes is the third-person singular present tense form of the verb secrete, meaning to produce and discharge a substance from a gland, tissue, or cell. In biological contexts, to secrete is to release materials that have a specific function in physiology, metabolism, or interaction with the environment. The term is commonly used across animals, plants, and microbes to describe how substances are produced and moved to their site of action.

Secretions are diverse and include enzymes, hormones, mucus, saliva, sweat, gastric juice, bile, and nectar. Exocrine secretions exit through ducts to an external surface or bodily cavity (for example, saliva into the mouth or pancreatic juice into the intestine). Endocrine secretions are released into the bloodstream to act at distant targets, such as insulin or adrenaline. Some secretions serve multiple roles depending on context and tissue.

Secretory mechanisms vary by tissue. Merocrine secretion releases product via exocytosis without damaging the secretory cell. Apocrine secretion involves release with a portion of the cell’s cytoplasm, while holocrine secretion releases whole cells that disintegrate to form the secretory product. Different glands predominantly use different modes, with sweat commonly described as merocrine and sebaceous glands traditionally associated with holocrine processes.

Beyond animals, plants secrete nectar, resins, essential oils, and mucilages, often for defense or reproduction. Microorganisms secrete enzymes and toxins that aid digestion or competition with other species. The study of secretion spans physiology, anatomy, botany, and microbiology.

Disruptions in secretion can signal disease or impact health, such as dry mouth from reduced saliva, thickened mucus in certain conditions, or impaired bile flow affecting digestion.