Source: Google
Tears are produced by tear glands or lacrimal glands situated near our eyes as a reflex to our emotions. They clean and protect our eyes. Tears contain sodium and hence they are salty.
When we cry, pressure is laid on lacrimal glands which causes swelling of eyes. Also since the tears contain salt,when they accumulate near eyes and cheek, they are absorbed by the skin and muscles. This causes dehydration near those areas. This attracts water from other parts of the body, which brings a swollen look to eyes.
Sodium in the tears cause irritation to the eyes and makes us to rub them. This causes redness of the eyes when we cry.
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