If you’ve ever had tears run down your cheeks into your mouth, you’ve probably noticed that they have a distinctly salty flavor.
Of course, there’s a lot more to tears that just a salty taste. Keep reading to learn what tears are made of, where they come from, how they protect and lubricate our eyes, and why a good cry may make us feel better.
- fatty oils
- over 1,500 different proteins
Tears are formed in three layers that work to lubricate, nourish, and protect our eyes:
- Outer layer. The oily outer layer is produced by the meibomian glands. This layer helps tears stay in the eye and keeps tears from evaporating too quickly.
- Middle layer. The watery middle layer includes water-soluble proteins. It’s produced by the main lacrimal gland and accessory lacrimal glands. This layer protects and nourishes the cornea and conjunctiva, which is the mucous membrane covering the inside of the eyelids and the front of the eye.
- Inner layer. The mucous inner layer is produced by goblet cells. It binds water from the middle layer, allowing it to spread evenly to keep the eye lubricated.
Tears are produced by glands located above the eyes and under your eyelids. Tears spread down from the glands and across the surface of your eye.
Some of the tears drain out through tear ducts, which are small holes near the corners of your eyelids. From there, they travel down to your nose.
In a typical year, a person will produce 15 to 30 gallons of tears, according to the American Academy of Ophthalmology (AAO).
There are three primary types of tears:
- Basal tears. Basal tears are in your eyes at all time to lubricate, protect, and nourish your cornea.
- Reflex tears. Reflex tears are produced in response to irritation, such as by smoke, wind, or dust. Reflex tears are what we produce when confronted with syn-propanethial-S-oxide from slicing onions.
- Emotional tears. Emotional tears are produced in response to pain, including physical pain, empathetic pain, sentimental pain, as well as emotional states, such as sadness, happiness, fear, and other emotional states.
Waking up with crust in the corners of your eyes is quite common. According to the University of Utah, these hardened bits are typically a mix of:
- exfoliated skin cells
While this mix is usually taken care of during the day by blinking, during sleep your eyes are closed and there’s no blinking. Gravity helps it collect and harden in the corners and at the edges of your eyes.
According to a
The beneficial effects of crying has been studied in
There’s also research about the composition of emotional tears. Scientists believe that emotional tears may contain proteins and hormones not typically found in basal or reflex tears. And these hormones
More research about the effects of crying and the composition of emotional tears is needed before we can determine whether they can provide emotional therapy.
Every time you blink, your tears clean your eyes. Tears keep your eyes smooth, moist, and protected from:
- the environment
- infectious pathogens
Your tears are salty because they contain natural salts called electrolytes.