Crying begins when your brain sends a signal to a small gland above each eye, triggering a flood of tears that spill faster than your eyelids can drain them away. But the full process involves much more than tear production. It’s a chain reaction that connects your emotions, your nervous system, your facial muscles, and even your throat, all working together in a response that appears to be unique to humans among all species.
Three Types of Tears, Three Different Jobs
Your eyes don’t just produce one kind of tear. There are three distinct types, each triggered differently and serving a different purpose.
Basal tears are the ones you never notice. Small accessory glands tucked under your eyelids release them continuously, coating the surface of your eye to keep it moist, nourished, and protected from dust and debris. You produce these every waking moment.
Reflex tears kick in when something irritates your eyes: chopping onions, walking into wind, or getting hit with bright light. Sensory nerve endings on the surface of your eye detect the environmental change and trigger a rapid flood of fluid from the main lacrimal gland to wash away and chemically neutralize the threat. These tears come on fast and in large volume.
Emotional tears are the ones people mean when they talk about crying. These are produced by the same lacrimal gland as reflex tears, but they’re triggered by feelings rather than physical irritation. People shed emotional tears at weddings, funerals, and the birth of children, but far more often during everyday moments: minor frustrations, arguments, sad movies, or a piece of music that catches you off guard.
What Happens Inside Your Body When You Cry
Emotional crying starts in the brain, not the eyes. When you experience a strong emotion, the areas of your brain that process feelings activate the part of your nervous system responsible for involuntary functions like heart rate and digestion. This is the parasympathetic nervous system, sometimes called the “rest and digest” system. It sends a signal along a nerve pathway to the lacrimal gland, which sits just above and to the outer side of each eye, telling it to produce tears.
At the same time, your body launches a whole-body response. Your breathing pattern changes, becoming irregular and sometimes gasping. The muscles in your face contract, pulling the corners of your mouth down and crinkling the skin around your eyes. Your chin may quiver. Your voice may crack or rise in pitch. During full sobbing, the muscles in your chest and abdomen spasm rhythmically, which is why crying hard can leave you physically exhausted.
One of the most recognizable sensations during crying is the “lump in the throat.” This happens because the muscles in your throat and larynx tense up. Specifically, the strap muscles in your neck contract and put pressure on the thyroid cartilage, while the sphincter at the top of your esophagus tightens. Your body is essentially trying to hold the airway wide open (a stress response), which conflicts with your attempts to swallow normally. That tension creates the tight, swollen feeling that makes it hard to speak or swallow when you’re about to cry.
Where Tears Go After They Leave Your Eyes
When you’re not crying, tears drain away as fast as they’re produced, which is why you don’t notice basal tears at all. The drainage system is surprisingly intricate. On the inner corner of each eyelid, there’s a tiny opening called the punctum, only about 0.2 to 0.3 millimeters wide. Tears flow into these openings and travel through small channels called canaliculi that run horizontally through the eyelid for about 8 millimeters, following the curve of your lid.
In about 90% of people, the upper and lower channels merge into a single short tube before emptying into the lacrimal sac, a small pouch roughly 12 to 15 millimeters long that sits collapsed against the side of your nose. From there, tears travel down through a duct that passes through the bone of your upper jaw and empties into your nasal cavity. This is exactly why your nose runs when you cry: the tears are literally draining into it.
During emotional crying, the lacrimal gland produces tears far faster than this drainage system can handle. The excess spills over the eyelid and rolls down your cheeks.
Why Humans Cry Emotionally
Humans are the only species known to shed tears in response to emotions. The leading scientific explanation is social. Crying evolved as a way to signal distress, vulnerability, or strong feeling to the people around you, strengthening social bonds and prompting help from others. Visible tears on someone’s face are hard to fake convincingly and impossible to hide easily, which makes them an honest signal. Researchers have concluded that the principal function of emotional crying is to promote social bonding and mutual supportive behavior.
This makes sense when you consider that infants cry vocally from birth, but their tear production is limited. Most full-term newborns can produce basal tears within the first day of life, with about 95% showing normal tear production by the end of their first week. However, reflex tearing in response to irritation doesn’t fully develop until one to seven weeks after birth. Premature infants have even more reduced tear secretion. For babies, the vocal cry is what matters: it’s the alarm that brings caregivers running. Tears become part of the signaling system later, as children grow and need more nuanced ways to communicate emotional states.
Does Crying Actually Make You Feel Better?
The popular idea that crying “releases toxins” or flushes stress hormones out of your body doesn’t hold up well under scientific testing. Studies measuring cortisol, the body’s primary stress hormone, have found no significant difference in cortisol levels between people who cried during a stressful task and those who didn’t.
What researchers have found is more subtle. Heart rate decelerates just before crying begins, then returns to baseline during the first period of tears. This suggests crying may help maintain your body’s physiological balance, not by purging chemicals but by activating a self-soothing process. The deep, rhythmic breathing that follows a bout of sobbing, along with the unconscious regulation of heart rate, appears to nudge your body back toward a calmer state. So the relief people feel after crying is likely real, but it comes from the physical act of calming down rather than from any special property of the tears themselves.
The social context matters too. People tend to feel better after crying when they receive comfort from someone else. Crying alone, or crying in a situation where the response is judgment rather than support, is much less likely to provide that sense of relief. This fits with the theory that crying’s core purpose is social connection: it works best when it achieves that goal.