So, what are tears? They are chemically very much alike with saliva, as they contain protein, salts and hormones, but the components of tears vary dependent on the type of tear produced. There are three types of tears that can be produced. The basal tear keeps your eyes moist and lubricated. Reflex tears, are a response of the body to remove particulates from the eyes. Psychic tears, these are that we get when we are feeling upset or other overwhelming emotions.
Image from Cavs
But, one of the most intriguing questions here is, not why we cry when we are in pain, but why we cry when we are upset. The limbic system, which acts self consciously, works by using acetylcholine - a neurotransmitter. The limbic system deals with human emotion and can influence the production of tears so when we get upset we produce tears.
Furthermore, tears are known to contain leucine enkephalin, a pain-killer, which could suggest why your state of mind improves and clears after a good cry. Tears also contain lysozyme, an antibacterial enzyme which works by attaching itself onto the carbohydrate molecules on the cell wall effectively rupturing it and allowing water to move into the bacteria by osmosis causing the bacterium to swell until it eventually bursts. Moreover, crying is thought to reduce amount of manganese which can lead to tiredness, aggression, anxiety and nervousness. Also, reflex tears have twenty four percent more albumin protein which transports toxic molecules. It has even been proposed that tears can reduce stress levels.
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