We cry for many reasons. The tears flow even when we try our to hold them in. Men have more testosterone, which inhibits tears. On the other hand, women have more prolactin, which stimulates tears.
Three different types of crying that exist, involving different mechanisms and chemicals. They are:
Emotional Crying: These tears are produced in such a large quantity. They flow down our cheeks and overflow and overwhelm the nasal canal of the tear ducts. Main causes of this type of crying: stress, frustration, sadness, and happiness, and any other emotion that evokes tears.
Basal Tears: A protein-rich antibacterial liquid is constantly secreted by the lacrimal gland. The gland is present in the outer edge of the eyeball. When we blink, the liquid is released, which then lubricates the entire eye surface. These tears protect eyes by lubricating them.