Tears

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Tears are a clear liquid secreted by the lacrimal glands (tear gland) found in the eyes of all land mammals.^[1] Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes.^[2] The different types of tears—basal, reflex, and emotional—vary significantly in composition.^[2]

The functions of tears include lubricating the eyes (basal tears), removing irritants (reflex tears), and also aiding the immune system.^[3] Tears also occur as a part of the body's natural pain response.^[4] Emotional secretion of tears may serve a biological function by excreting stress-inducing hormones built up through times of emotional distress.^[5][6] Tears have symbolic significance among humans.^[4]